Research ArticlePolyfunctional Modifiers for Bitumen and BituminousMaterials with High Performance

Alim Feizrakhmanovich Kemalov Ruslan Alimovich KemalovIlmira Maratovna Abdrafikova Pavel Sagitovich Fakhretdinovand Dinar Zinnurovich ValievDepartment of High-Viscosity Oil and Natural Bitumen Kazan (Volga Region) Federal University 18 Kremlyovskaya StreetKazan 420008 Russia

Correspondence should be addressed to Alim Feizrakhmanovich Kemalov alimkemalovmailru

Received 8 March 2017 Revised 15 July 2017 Accepted 24 August 2017 Published 3 January 2018

Academic Editor Hainian Wang

Copyright copy 2018 Alim Feizrakhmanovich Kemalov et al This is an open access article distributed under the Creative CommonsAttribution License which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

Over the last decade increase in capacity and the intensity of vehicular traffic has increased manifoldly including heavy truckssuper singles and higher tire pressures resulting in significant increase of dynamic loads on the road surface which in turn leadto high quality requirements for bitumen in order to avoid premature wear and failure of asphalt concrete pavements One of thepossibilities to increase the quality of bitumen is to use special additives and modifiers that can provide a high adhesion to mineralfiller and inhibit the aging anddegradation processes in the asphalt coating To achieve this in the present study compositemodifiersbased on bisimidazolines derivatives were synthesized The developed polyfunctional modifier (PFM) of complex action providesenhanced thermal stability significantly improves the adhesion between bitumen binder and aggregates and also improves thephysical-mechanical properties of the asphalt concrete Based on the test results it is recommended to use the synthesized samplesof the PFM additive with complex action in asphalt mixtures for road paving

1 Introduction

Asphalt concrete (AC) coatings include two main compo-nents bitumen and aggregates (crushed stone) Bitumenperforms the function of a substance that binds particles ofmineral material to form an asphalt concrete coating Beingnonpolar bitumen has high waterproofing properties It isknown that high-resinous and low-paraffinic petroleum is themost suitable for the production of road and constructionbitumen However due to the limited supply of this type ofpetroleum almost any oil residues are used As a result thequality of bitumen is very unsure at the moment and thatleads to poor quality of bituminous materials resulting inpoor quality asphalt concrete pavements

At the same time most of the used aggregates have agreater affinity for water than they do for bitumen binder [1ndash3] Polycyclic aromatic compounds resins and heteroatomiccompounds contained in the bitumen do not provide desiredadhesion to the mineral part of asphalt concrete Oxygenated

compounds formed during the oxidation of vacuum residuesalso have little impact on the adhesive properties of bitumen[4ndash7]

Poor adhesion between the bitumen binder (BB) andaggregate may lead to stripping (delamination of the binderfrom the aggregate surface) in the presence of water whichleads to pavement failure such as raveling potholes forma-tion and rutting [2 3 6ndash8] The situation is aggravatedby the continuous increase in capacity and traffic volumesincluding heavy truck axle loads super singles and hightire pressure that leads to a significant increase of dynamicloads on the pavement Therefore to obtain high qualitypavements key factor is in ensuring high adhesion betweenbitumen and the mineral component of pavement For thisreason adhesion additives are used most frequently these arecationic surfactants [3 7ndash11] Classical cationic surfactantsare diphilic structures in which nonpolar part is a long chainhydrophobic alkyl and the polar part (so-called ldquoheadrdquo) isa positively charged ammonium center or nitrogen atom

HindawiAdvances in Materials Science and EngineeringVolume 2018 Article ID 7913527 15 pageshttpsdoiorg10115520187913527

2 Advances in Materials Science and Engineering

capable of being protonated in acidic mediums This fun-damental property diphilicity is the reason why surfactantsare lined up at the interface ldquobitumen-mineral materialrdquo [5ndash9] Herewith the positively charged (hydrophilic) groupsare fixed on polar surface of the mineral material and thehydrophobic hydrocarbon chains are fixed in the bitumenThus the adhesive additive acts as bridge between bitumenbinder and aggregates that is schematically presented inFigure 1

Nowadays imidazolines and their derivatives (IandashI) aswell as bisimidazolines (IIa II3) [9 11 12] that exhibitthe ability to increase the bitumen adhesion to mineralmaterial are most widely used as additives for bitumenthe mechanism of their action is shown schematically onFigure 2 Adhesion additive ldquoAmidanrdquo [12] which presentsthe technical product containing a mixture of imidazoline(IandashI) and bisimidazoline (IIa II3) derivatives can be takenas example

N N

R (IIa)

N N

R

N N

R(IIб)

N N

R

NH

N N X

R(I)

（2

（2 （2 （2 （2

（2

where R = alkyl or alkenyl (in all the structures (I-II)) X arethe possible substituents in (I) with the following structures(I1ndash)

X = H (Iа)X = C（2ndashC（2ndashN（2 (Iб)

O

X = C（2ndashC（2ndashNHndashCndashR (Iв)

X = C（2ndashC（2ndashNHndashC（2ndashC（2ndashN（2 (Iг)

O

X = C（2ndashC（2ndashNHndashC（2ndashC（2ndashNHndashCndashR (Iд)

Composite modifiers such as sulfur rubber (polybu-tadiene natural rubber butyl rubber chloroprene etc)organic-manganese compounds thermoplastic polymers(polyethylene polypropylene polystyrene ethylene-vinylacetate (EVA)) thermoplastic rubbers (polyurethane olefincopolymers and block copolymers of styrene-butadiene-styrene (SBS)) are also used in order to improve physical-chemical properties of BB as well as the physical-mechanicalproperties of AC [13ndash15]

The effectiveness and quality of additives are largelyrelated to their thermal stability and this is due to thefollowing reasons (most relevant for Russia)

(1)Roadbitumen is produced in bulk by liquid-phase oxi-dation of vacuum residue the optimal process temperatureis 250∘C and it is more viable to inject the additive to theoxidized bitumen directly at its outlet from the oxidation col-umn to obtain bitumen with improved adhesion properties(2) The hot-mix asphalt concrete is the most used in

road construction and the compounding of bitumen withmineral material is carried out at relatively high temperatures(160ndash170∘C)

It should be emphasized that a disadvantage of modernadhesivemodifiers for bitumen is that they demonstrate a lowthermal resistance (up to 120ndash175∘C) while for some systemsthere is a rapid loss of adhesion at 150∘C On the other handtheir use often leads to deterioration of physical-mechanicalproperties of the corresponding AC [16]

Thus the aim was to develop the new modifiers withincreased thermal stability (up to 220ndash240∘C) that wouldbe capable of increasing the adhesion between bitumen andaggregates and improving elasticity of the binder that is thepolyfunctional modifiers (PFM)

2 Materials and Methods

According to the concept of nonclassic cationic surfactants[17 18] they have hydrophobic hydrocarbon chains whichare fragmented (broken) by polar heteroatomic groups Thisstructure ensures their physical and chemical properties andadsorption behavior different from the classic surfactantsBased on this concept high-performance chemicals wereobtained that were useful for the production treatment andtransportation of petroleum as well as for the productionof corrosion inhibitors emulsifiers demulsifiers the biologi-cally active substances and so on [17ndash19] We used the sameconcept to develop desired nitrogen-containing compounds

21 Modifiers Synthesis In accordance with the concept ofnonclassical surfactants we had assumed that it is neces-sary to increase polarity of the molecule of constructedimidazolines by increasing the number of polar imidazolinecenters from one to two in order to create compounds withneeded properties as well as to introduce nonclassical spacerinto the molecule wherein the hydrophobicity of an alkylchain is broken (fragmented) by one or more alkanoylamidefragments

C O

N

R

n

（2 （2

On one hand this structure of the spacer providesan increase in the molecule polarity that is responsiblefor interaction between bitumen and hydrophilic surfaceof the aggregates because extra polar amide groupsappear along with two imidazoline cycles On the

Advances in Materials Science and Engineering 3

Figure 1 Cationic surfactants as a bridge between the bitumen and aggregates

NN

NC

O

NC O

NN

Mineral material

Bitumen

+ +

NC

O

nminus1

Figure 2 Location of bisimidazoline molecules on the interface ldquobitumen-mineral materialrdquo

other hand the use of alkanoylamide fragments allowsintroducing additional hydrophobic long chain alkylgroups which increase the possibility of adhesive tofix in the bitumen media This enhances the adhesiveproperties of the designed compounds As a result we

obtained N-acylated bisimidazolines with (ethylene-N-alkanoylamide) spacers namely 1-(21-alkylimidazolinyl-11)-2-[(22-alkylimidazolinyl-12)-poly(ethylene-N-alkanoylam-ide)]ethanes containing two imidazoline cycles connectedby spacers

N N

R

N N

R

N

C O

R

n

(IIIаndashIIIв)

（2（2 （2 （2（2 （2

where R = CH3ndash(CH2)7ndashCH=CHndash(CH2)7ndash 119899 = 1 (IIIa) 119899 =2 (III3) and 119899 = 3 (IIIk)

The authors assumed that this construction of the additivewould lead to increasing of bitumen adhesion to the mineralcomponent of pavement Furthermore the conversion ofthe secondary amino groups into alkanoylamides shouldalso increase significantly the thermal stability of designedcompounds due to the fact that tertiary amides are morestable than the starting amine-compounds

The desired spacers were obtained with the average yield(the ratio of the mass of the obtained product to the mass ofthe starting material) of up to 90 and are viscous and pastybrown liquids the physicochemical characteristics of whichare given in Table 1

The starting amino-compound and the resulting com-pounds were analyzed by the conventional method of poten-tiometric titration of a mixture of primary secondary andtertiary amines with the definition of the total basicity BTthe basicity of secondary and tertiary amines B23 and thebasicity of tertiary amines B3 Then the joint basicity oftertiary amines and amides B3+amide was determined bypotentiometric titration of the sampleweight of test substancein acetic anhydride (as solvent) with the use of 01 N solutionof HClO4 in glacial acetic acid The basicity of amidesBamide was determined by the difference between the basicityB3+amide and the basicity B3 [20] The results of obtainedcompounds analysis are shown in Table 1

The FTIR spectra of the additives and the originalbitumen are presented in Figure 3

4 Advances in Materials Science and Engineering

Table 1 Physicochemical characteristics of N-acylated bisimidazolines derivatives (IIIandashIIIk)

CompoundElement analysisfoundcalculated

Basicity of amidesml 01 N HClO4gfoundcalculatedC N

(III1) 78577864 729740 10491056

(III3) 78417851 663670 15851594

(IIIk) 78327843 619628 19181921

100

80

60

40

20

0

1600 1400 1200 1000 800

(a)

100

80

60

40

20

0

1600 1400 1200 1000 800

(b)

Figure 3 IR spectra of the additives (a) and the original bitumen BND 6090 (TAIF-NK) (b)

Absorption bands with the following wave numbers wereobserved in the IR spectra of the obtained compounds (Fig-ure 3(a)) 120592C=N = 1600ndash1630 cmminus1 indicating the presenceof imidazoline cycles 120592C= = 1740ndash1745 cmminus1 120592ndashN(CO)R= 1660 cmminus1 and 120592CN = 1260ndash1300 cmminus1 can be related toalkanoylamide structures 120575(CH2)x = 720 cm

minus1 ndash correspondsto pendular oscillation of alkylene structure in a chain [21]Wide absorption bands at 1600 cmminus1 in FTIR spectra of theoriginal bitumen (Figure 3(b)) stand for the 120592CH bond inaromatic ring sharp absorption bands with high intensity at1440 and 1460 cmminus1 correspond to stretch vibration of ndashCH2ndashstructure fragment in long chains confirming high contentof paraffin waxes absorption band at 1375 cmminus1 is related tomethyl groups

22 Bitumen Modification and Performance Properties Analy-sis Investigation of the effect of the synthesized compoundson the adhesion between bitumen and the mineral materialwas carried out by the use of example of oxidized bitumen of6090 penetration grade (BND 6090 (the mark of bitumenin Russia means ldquopetroleum bitumen for roadsrdquo)) that wasproduced in TAIF-NK PSC with the following group chem-ical composition wt 2262 of saturates (including 102 of paraffin waxes) 1514 of aromatics 4026 of resins 2198 ofasphaltenes

The bitumen modification process was carried out asfollows

(1) The BND was heated in a metal vessel to the tem-perature of 80∘C with the use of stirring mechanismkept under thermostatic control for 20min to obtainhomogeneous diluted substance with homogeneousdistribution of components

(2) The BND was gradually heated to the temperature of120ndash130∘C at which it was kept for 20min

(3) Obtained PFM substances were injected into theheated bitumen and stirred for 20ndash30min to ensurehomogenous dispersion of the PFM in bitumenmedia

The adhesion between bitumen and aggregates (mineralmaterial) testing was conducted in accordance with GOST(GOST Russian state standard) 12801-98 [22] the essence ofwhich is to determine the ability of the viscous bitumen thatis precoated on the surface of mineral material to persist onit while being exposed by water The quality of the adhesionassessment was rated according to Table 2

The ability of bitumen to coat aggregates was evaluatedbased on contact angle measurement Original BND 6090and modified by PFM in amount of 06 08 10 and 12 wtwere taken The contact angle of wetting was determinedon two surfaces on glass which is the standard of thepolar surface as well as mineral rocks of various genesis(dolomitized limestone consisting of 90 dolomite and 10calcite) from ldquoBianca gravel factoryrdquo chemical compositionsof which are presented in Tables 3-4 Pervouralsk aggregateswere considered to be of ldquoacidicrdquo nature Bianca ndash is of ldquobasicrdquonature

Measurements were carried out using cathetometer KM-8 by direct measurement of the base and height of the dropwith subsequent calculation [23] The cosine of the contactangle of the drop is calculated by the formula

cos 120579 = 1199032 minus ℎ2

1199032 + ℎ2 (1)

where 119903 = 1198712 is the droplet radius 119871 is the droplet baseand ℎ is the droplet height With the help of a cathetometerthe contact angles of the taken aggregates wetting by bitumen

Advances in Materials Science and Engineering 5

Table 2 Evaluation of grip (adhesion)

Feature of the bitumen film on the surface of crushed stone Evaluation of gripBinder film is completely retained on the surface local decreasing of the thickness of a film can be observed Excellent (five points)Binder film is completely retained on the surface but is partially separated from the sharp corners and edges Good (four points)Binder film is retained on over 50 of crushed stone surface Satisfactory (three points)Binder film is retained on less than 50 of crushed stone surface On the exposed surface individual bitumendroplets are observed Poor (two points)

Table 3 Chemical composition of the ldquoPervouralsk mine managementrdquo gravel

Content in terms of dry matter wtSiO2 TiO2 Al2O3 Fe2O3 FeO CaO MgO MnO K2O Na2O V2O5 P2O5 S221 327 117 272 169 89 90 023 02 014 04 001 003

Table 4 Chemical composition of the ldquoBianca gravel factoryrdquo gravel

Content in terms of dry matter wtSiO2 Fe2O3 CaO MgO Al2O3 SO3 ]3щ CaCO3 MgCO333 07 209 119 08 03 372 249

binder samples were determined The drop of bitumen (ofthe same size and mass as far as possible) was laid onto thesurface of a substrate at a bitumen temperature of 130∘CAs the drop of bitumen cools instantly as soon as it reachesthe cold substrate surface the samples of the stone materialswere heated to 40∘C which practically did not change thesurface properties of the rock but retained the liquid stateof the bitumen for a sufficient time The equilibrium valueof the wetting contact angle was determined on the basis ofthe kinetic curves The wetting angle was measured twiceimmediately after the dropping of the bitumen and after 1minute necessary to achieve equilibrium wetting angle Thelatest value was taken into account

It is known that adhesion of bitumen tomineral materialsis the work required to separate the bitumen layer from thesematerials In order to determine the work of adhesion (aquantitative measure) between aggregates and bitumen wemeasured the surface tension of bitumen in the presence ofthe PFM Surface tension at the interface between binder andair phases (120590BA) is the most important factor determining theintensity of wetting of amineral substrate by bitumen Surfacetension measurements were carried out at a temperature of25∘Cusing EasyDyne S K20S tensiometer (KRUSS) by theDuNui ring method Bitumen samples were dissolved in tolueneat a mass ratio of toluene bitumen equal to 1 15

Based on the obtained values of 120579 and 120590 the wettingenergy or the adhesive stress was calculated

119882119890 = 120590 times cos 120579 (2)

The work of adhesion was calculated using Young-Dupreequation

119882119886 = 120590 times (1 + cos 120579) (3)

The work of cohesion was calculated to assess the interac-tion strength between the bitumen components The work of

cohesion is determined by the expenditure of energy on thereversible rupture of the body over a section equal to unit ofarea Since as a result of a rupture a surface with two-unitarea forms the work of cohesion is as follows

119882119896 = 2120590 (4)

To characterize the wetting process the spreading coeffi-cient 119878 is used which is taken as the difference between thework of adhesion119882119886 and the work of cohesion119882119896 For thecomplete wetting 119878 rarr 0

119878 = 119882119886 minus119882119896 = 120590119897 times (cos 120579 minus 1) (5)

The relationship between the work of adhesion andcohesion can be expressed through a relative value a relativeadhesion work of liquid 119885119886

119885119886 =119882119886

119882119896 (6)

If 119882119886 and 119882119896 are expressed in terms of the quantitiesdefined in (3) and (4) then

119885119886 =1 + cos 1205792 (7)

To study the dynamic viscosity (according to ASTMD4402) of modified bitumen samples dynamic tests werecarried out using Rheotest RN 41 We obtained the depen-dence of dynamic viscosity (mPasdots) from temperature (∘C)at a constant shear rate (100 sminus1) The measurements werecarried out in the following way first the measuring systemldquocone-platerdquo was heated to 125∘b on which bitumen sampleswere laid (original bitumen and the bitumenmodified by 0608 10 and 12 wt of PFM resp) then the measurementswere taken along with cooling of the samples In order tostudy the thixotropic properties of the samples immediately

6 Advances in Materials Science and Engineering

Table 5 Physical-chemical characteristics of the PFM

Number The name of indicators The meaning Testing method(1) Appearance The viscous honey-like mass Visually(2) Colour From light yellow to dark brown Visually(3) Smell Weak characteristic Organoleptic(4) Density at 20∘C gcm3 09538 GOST 3900-85(5) Kinematic viscosity at 100∘C mm2s 1396 GOST 33-2000

(a) (b)

Figure 4 The results of the impact of adhesion additive on the adhesion between bitumen and aggregates (a) the original bitumen 6090without additive (b) bitumen with 1 wt of PFM

after direct measurements the viscosity was measured in theopposite direction with a decrease in the shear rate from 1000to 1 sminus1 at temperatures of 80ndash120∘C

The properties of binders such as softening temperature(EN 1427 ASTMD36 AASHTOT53) brittleness temperatureaccording to Fraas (ie the Fraass Breaking Point EN 12593-2013) penetration (EN 1426 ASTM D5 AASHTO T49)ductility (EN 133981358713589 ASTM D 113 AASHTO T51) and the change of the bitumen softening temperatureafter heating were determined according to GOST 22245-90 ldquoViscous petroleum road bitumenrdquo [24] First bitumensamples are heated in the drying oven at a temperature of163∘C for 5 hours in accordance with GOST 18180-72 [25]after which the softening temperature is determined Densityat 20∘C and kinematic viscosity at 100∘C were determined inaccordancewithGOST 3900-85 [26] andGOST 33-2000 [27]respectively

The thermal stability test of modified bitumen was carriedout at temperatures of 163 180 and 200∘C and a heatingduration of 25 hours (max) with the use of stone materialsof basic and acidic nature The temperature of 163∘C isspecified by GOST 18180-72 [25] and ASTM D 2872 [28]The temperatures of 180 and 200∘C were chosen upon therecommendations of road constructing organizations Themodified bitumen that was under a thermal exposure wassampled every 5 hours and then the adhesion test wasconducted according to the above-mentioned techniqueBitumen binder can be stored at bitumen storage where it isconstantly heated to keep fluidness formaximum 24 h beforeit is directed to an asphalt concrete mixing vessel For thatreason the maximum duration of heating (25 h) was chosenthat exceeds possible storage period

Pilot-scale tests were also conducted as well as thetechnical inspection of asphalt concrete mixtures the resultsof the latest were compared with the GOST 9128-2009 [29]requirements

3 Results and Discussion

31 Comparative Study of the Obtained Additives and TheirEffect on Bitumen Properties The features and advantages ofthe PFM compared to adhesive ldquoAmidanrdquo are the followinghigh adhesion (at high temperatures aswell) thermal stabilityat 250ndash270∘C within 4 hours (compared to the values of120ndash175∘C) high flash point and high processability thepossibility of dosing directly into the bitumen that is outflowof the oxidizing columnwith a temperature up to 280∘C PFMincludes both polymer and adhesive characteristics whichaffects the production costs Despite the fact that additive isdoped in small amounts (up to 08ndash10 wt) they also affectthe physical-chemical properties of the finalACThe speciallydesigned spacerrsquos structure enables starting of secondarypolymerization processes taking place between asphaltenicand resinous compounds in bitumen media

Physical-chemical characteristics of the synthesized PFMare presented in Table 5

Research of the polyfunctional modifier influence onthe adhesion between bitumen and the aggregates (mineralmaterial) was carried on the above-mentioned sample of6090 bitumen of OAO TAIF-NK production with thecharacteristics shown in Table 6 As it can be seen fromthe data in Table 6 proposed compounds added at amountsof 05ndash10 have improved adhesion between bitumen andthe mineral filler surface corresponding to five points inaccordance with GOST 12801-98

Pictures taken after the performed adhesion test arepresented on Figure 4 When a mineral material is coated

Advances in Materials Science and Engineering 7

Table6Re

sults

oftheq

ualitytests

ofbitumen

mod

ified

with

theu

seof

synthesiz

edcompo

unds

Com

poun

dDosage

Softe

ning

temperature

∘b

Penetration

01m

mDuctilitycm

Adhesio

npo

ints

Brittlenesstemperature

byFraas∘b

Thec

hangeo

fbitu

men

softe

ning

pointafte

rheatin

g(Δ119905 soft)∘b

25∘b

0∘b

25∘b

0∘b

Orig

inalbitumen

mdash497

6722

8455

2minus23

50

Com

poun

d(IIIa

)(119899=1)

01

495

6722

8455

3minus23

mdash025

493

7023

8455

4minus24

30

05

4972

2484

55

5minus26

21

10488

7525

8556

5minus27

1015

485

7826

8657

5minus27

mdash

Com

poun

d(III3)

(119899=2)

01

495

6722

8455

3minus23

mdash025

493

6722

8455

4minus24

32

05

4968

2384

55

5minus26

20

10488

6923

8556

5minus27

1015

485

7024

8657

5minus27

mdash

Com

poun

d(IIIk)

(119899=3)

01

496

6722

8455

3minus23

mdash025

495

6722

8455

4minus24

35

05

493

6823

8455

5minus26

23

10490

6923

8556

5minus27

1015

486

7024

8657

5minus27

mdash

ldquoAmidanrdquo

01

45120

3mdash

025

45120

470

05

45120

565

1046

115

560

1546

115

550

8 Advances in Materials Science and Engineering

Table 7 Surface tension of the bitumen samples

Bitumen samples Original PFM content wt06 08 10 12

Average value 120590119897 mNm 3304 3138 3134 3146 3142

with the original bitumen (ie without modifying additives)the binder film is persistent on the area of less than 50 ofstonesrsquo surface corresponding to 2 points Addition of 1 wtofmodifier leads to complete coverage of themineralmaterialsurface corresponding to 5 points

The use of PFM improves the thermal stability of bitumen(Table 6) Thus bitumen with PFM additive amounts of09ndash10 wt has lowΔ119905soft equal to 1

∘Cwhile for the bitumenwith ldquoAmidanrdquo Δ119905soft equals 6∘C In addition there has beenimprovement in the penetration which indicates the bitumenbinder improved plasticity

The test results indicate the fact that the increase in thecontent of adhesive additives in the range from 0 to 15 wtleads to increase of penetration values (at 25∘C) namely from67 to 78 (01mm) respectively (Table 6)

The results of adhesive additive ldquoAmidanrdquo testing (Table 6)indicate deterioration of the bitumen properties Though theadhesion is equal for both adhesives ldquoAmidanrdquo acts as adiluting agent leading to increase in the penetration valueThe latest would lead to fractionation (ie delamination)of the binder in the process of its application The changesof ldquoAmidanrdquo-modified bitumen softening temperatures afterheating are too high do not meet the standard requirementsand mean low stability of the binder For that reason no fur-ther tests were carried out for bitumen containing ldquoAmidanrdquo

Regarding the brittleness temperature determinedaccording to Fraas (the Fraass Breaking Point) it indicatesthe lower temperature at which the bitumen loses viscoplasticproperties and as a consequence becomes brittle It is knownthat the lower the brittle point the wider the temperaturerange in which the bitumen is in the viscoplastic state andtherefore the better its physical-mechanical characteristicsIn this case the additive doping allows reducing the brittlepoint and consequently providing expansion of ductilitytemperature range Apart from the above-mentionedadvantages it should be noted that the compounds aresuperior to ldquoAmidanrdquo in adhesion at high temperaturesThus the modified bitumen with additives amount of09ndash10 wt shows high adhesion to sand (5 points) afterthermal exposure at temperatures of 220ndash240∘C for 12 hoursIt should be noted that the bitumen with the same amountsldquoAmidanrdquo exhibits much lower thermal stability providingsimilar adhesion only at temperatures above 170∘C

32 Contact Angle Measurements and Adhesion Work Calcu-lation Figure 5 shows the dependence of the glass surfacewetting contact angle on the content of the additive It isestablished that bitumen does not wet the glass becausecos 120579 has negative values Doping the proposed additive into

bitumen results in a slight increase in wetting ability anextremum is observed with an additive content of 08

Figure 6 shows the dependence of the aggregates wettingcontact angle on the content of the additive It can be seen thatthe presence of an additive significantly changes the wettingof the mineral substrate by the modified bitumen a wettinginversion is observed that is cos 120579 increases with increasingcontent of the additive and acquires positive values We notethat in the case of the surface of mineral materials anextremum is also observed with an additive content of 08by weight

Surface tension measurements results are presented inTable 7

The data in Table 7 indicates that the surface tensiondecreases with the addition of the additive This agrees withthe data of [30] that the surface tension at the bitumen-solidinterface decreases with increasing of surfactants contentSurface tension in combinationwith adhesion properties pro-vides information of the strength of the bitumen adherence tomineral material

The calculated values of the above-mentioned charac-teristics of the ldquoaggregates-organic binderrdquo system surfaceproperties that is wetting energy adhesion work cohesionwork spreading coefficient and relative adhesion work arepresented in Table 8

The analysis of the obtained data shows that the PFMbeing adsorbed at the interface promotes better wetting ofthe aggregates surface with bitumen In this case the contactangle 120579 decreases the spreading coefficient and relativeadhesion work increase reaching a peak when an additivecontent is 08 wt and cohesion work is reduced

The value of119885119886 approaches 1 Consequently the adhesionforces between bitumen and mineral materials approximatein magnitude to the binding forces of the bitumenmoleculesThis contributes to the formation of a material with ahomogeneous defect-free structure

33 Component Composition and Dispersity of the BitumenInformation on the component composition can play animportant role in studying the changes occurring as a resultof bitumen modification (Table 9) Thus when introducingthe developed additive into the initial bitumen in an amountof about 1 by weight mainly the content of saturates inthe direction of decrease and asphaltenes in the direction ofincrease is changing In this case the relative and absolutechanges of the remaining groups of components are insignif-icant

The sequence of hydrocarbon group transitions in thiscase can be delineated as follows [31]

Aromatics (PCA) 997888rarr aromatics (MCA)larr997888 saturates 997888rarr asphaltenes (8)

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

Advances in Materials Science and Engineering 3

Figure 1 Cationic surfactants as a bridge between the bitumen and aggregates

NN

NC

O

NC O

NN

Mineral material

Bitumen

+ +

NC

O

nminus1

Figure 2 Location of bisimidazoline molecules on the interface ldquobitumen-mineral materialrdquo

other hand the use of alkanoylamide fragments allowsintroducing additional hydrophobic long chain alkylgroups which increase the possibility of adhesive tofix in the bitumen media This enhances the adhesiveproperties of the designed compounds As a result we

obtained N-acylated bisimidazolines with (ethylene-N-alkanoylamide) spacers namely 1-(21-alkylimidazolinyl-11)-2-[(22-alkylimidazolinyl-12)-poly(ethylene-N-alkanoylam-ide)]ethanes containing two imidazoline cycles connectedby spacers

N N

R

N N

R

N

C O

R

n

(IIIаndashIIIв)

（2（2 （2 （2（2 （2

where R = CH3ndash(CH2)7ndashCH=CHndash(CH2)7ndash 119899 = 1 (IIIa) 119899 =2 (III3) and 119899 = 3 (IIIk)

The authors assumed that this construction of the additivewould lead to increasing of bitumen adhesion to the mineralcomponent of pavement Furthermore the conversion ofthe secondary amino groups into alkanoylamides shouldalso increase significantly the thermal stability of designedcompounds due to the fact that tertiary amides are morestable than the starting amine-compounds

The desired spacers were obtained with the average yield(the ratio of the mass of the obtained product to the mass ofthe starting material) of up to 90 and are viscous and pastybrown liquids the physicochemical characteristics of whichare given in Table 1

The starting amino-compound and the resulting com-pounds were analyzed by the conventional method of poten-tiometric titration of a mixture of primary secondary andtertiary amines with the definition of the total basicity BTthe basicity of secondary and tertiary amines B23 and thebasicity of tertiary amines B3 Then the joint basicity oftertiary amines and amides B3+amide was determined bypotentiometric titration of the sampleweight of test substancein acetic anhydride (as solvent) with the use of 01 N solutionof HClO4 in glacial acetic acid The basicity of amidesBamide was determined by the difference between the basicityB3+amide and the basicity B3 [20] The results of obtainedcompounds analysis are shown in Table 1

The FTIR spectra of the additives and the originalbitumen are presented in Figure 3

4 Advances in Materials Science and Engineering

Table 1 Physicochemical characteristics of N-acylated bisimidazolines derivatives (IIIandashIIIk)

CompoundElement analysisfoundcalculated

Basicity of amidesml 01 N HClO4gfoundcalculatedC N

(III1) 78577864 729740 10491056

(III3) 78417851 663670 15851594

(IIIk) 78327843 619628 19181921

100

80

60

40

20

0

1600 1400 1200 1000 800

(a)

100

80

60

40

20

0

1600 1400 1200 1000 800

(b)

Figure 3 IR spectra of the additives (a) and the original bitumen BND 6090 (TAIF-NK) (b)

Absorption bands with the following wave numbers wereobserved in the IR spectra of the obtained compounds (Fig-ure 3(a)) 120592C=N = 1600ndash1630 cmminus1 indicating the presenceof imidazoline cycles 120592C= = 1740ndash1745 cmminus1 120592ndashN(CO)R= 1660 cmminus1 and 120592CN = 1260ndash1300 cmminus1 can be related toalkanoylamide structures 120575(CH2)x = 720 cm

minus1 ndash correspondsto pendular oscillation of alkylene structure in a chain [21]Wide absorption bands at 1600 cmminus1 in FTIR spectra of theoriginal bitumen (Figure 3(b)) stand for the 120592CH bond inaromatic ring sharp absorption bands with high intensity at1440 and 1460 cmminus1 correspond to stretch vibration of ndashCH2ndashstructure fragment in long chains confirming high contentof paraffin waxes absorption band at 1375 cmminus1 is related tomethyl groups

22 Bitumen Modification and Performance Properties Analy-sis Investigation of the effect of the synthesized compoundson the adhesion between bitumen and the mineral materialwas carried out by the use of example of oxidized bitumen of6090 penetration grade (BND 6090 (the mark of bitumenin Russia means ldquopetroleum bitumen for roadsrdquo)) that wasproduced in TAIF-NK PSC with the following group chem-ical composition wt 2262 of saturates (including 102 of paraffin waxes) 1514 of aromatics 4026 of resins 2198 ofasphaltenes

The bitumen modification process was carried out asfollows

(1) The BND was heated in a metal vessel to the tem-perature of 80∘C with the use of stirring mechanismkept under thermostatic control for 20min to obtainhomogeneous diluted substance with homogeneousdistribution of components

(2) The BND was gradually heated to the temperature of120ndash130∘C at which it was kept for 20min

(3) Obtained PFM substances were injected into theheated bitumen and stirred for 20ndash30min to ensurehomogenous dispersion of the PFM in bitumenmedia

The adhesion between bitumen and aggregates (mineralmaterial) testing was conducted in accordance with GOST(GOST Russian state standard) 12801-98 [22] the essence ofwhich is to determine the ability of the viscous bitumen thatis precoated on the surface of mineral material to persist onit while being exposed by water The quality of the adhesionassessment was rated according to Table 2

The ability of bitumen to coat aggregates was evaluatedbased on contact angle measurement Original BND 6090and modified by PFM in amount of 06 08 10 and 12 wtwere taken The contact angle of wetting was determinedon two surfaces on glass which is the standard of thepolar surface as well as mineral rocks of various genesis(dolomitized limestone consisting of 90 dolomite and 10calcite) from ldquoBianca gravel factoryrdquo chemical compositionsof which are presented in Tables 3-4 Pervouralsk aggregateswere considered to be of ldquoacidicrdquo nature Bianca ndash is of ldquobasicrdquonature

Measurements were carried out using cathetometer KM-8 by direct measurement of the base and height of the dropwith subsequent calculation [23] The cosine of the contactangle of the drop is calculated by the formula

cos 120579 = 1199032 minus ℎ2

1199032 + ℎ2 (1)

where 119903 = 1198712 is the droplet radius 119871 is the droplet baseand ℎ is the droplet height With the help of a cathetometerthe contact angles of the taken aggregates wetting by bitumen

Advances in Materials Science and Engineering 5

Table 2 Evaluation of grip (adhesion)

Feature of the bitumen film on the surface of crushed stone Evaluation of gripBinder film is completely retained on the surface local decreasing of the thickness of a film can be observed Excellent (five points)Binder film is completely retained on the surface but is partially separated from the sharp corners and edges Good (four points)Binder film is retained on over 50 of crushed stone surface Satisfactory (three points)Binder film is retained on less than 50 of crushed stone surface On the exposed surface individual bitumendroplets are observed Poor (two points)

Table 3 Chemical composition of the ldquoPervouralsk mine managementrdquo gravel

Content in terms of dry matter wtSiO2 TiO2 Al2O3 Fe2O3 FeO CaO MgO MnO K2O Na2O V2O5 P2O5 S221 327 117 272 169 89 90 023 02 014 04 001 003

Table 4 Chemical composition of the ldquoBianca gravel factoryrdquo gravel

Content in terms of dry matter wtSiO2 Fe2O3 CaO MgO Al2O3 SO3 ]3щ CaCO3 MgCO333 07 209 119 08 03 372 249

binder samples were determined The drop of bitumen (ofthe same size and mass as far as possible) was laid onto thesurface of a substrate at a bitumen temperature of 130∘CAs the drop of bitumen cools instantly as soon as it reachesthe cold substrate surface the samples of the stone materialswere heated to 40∘C which practically did not change thesurface properties of the rock but retained the liquid stateof the bitumen for a sufficient time The equilibrium valueof the wetting contact angle was determined on the basis ofthe kinetic curves The wetting angle was measured twiceimmediately after the dropping of the bitumen and after 1minute necessary to achieve equilibrium wetting angle Thelatest value was taken into account

It is known that adhesion of bitumen tomineral materialsis the work required to separate the bitumen layer from thesematerials In order to determine the work of adhesion (aquantitative measure) between aggregates and bitumen wemeasured the surface tension of bitumen in the presence ofthe PFM Surface tension at the interface between binder andair phases (120590BA) is the most important factor determining theintensity of wetting of amineral substrate by bitumen Surfacetension measurements were carried out at a temperature of25∘Cusing EasyDyne S K20S tensiometer (KRUSS) by theDuNui ring method Bitumen samples were dissolved in tolueneat a mass ratio of toluene bitumen equal to 1 15

Based on the obtained values of 120579 and 120590 the wettingenergy or the adhesive stress was calculated

119882119890 = 120590 times cos 120579 (2)

The work of adhesion was calculated using Young-Dupreequation

119882119886 = 120590 times (1 + cos 120579) (3)

The work of cohesion was calculated to assess the interac-tion strength between the bitumen components The work of

cohesion is determined by the expenditure of energy on thereversible rupture of the body over a section equal to unit ofarea Since as a result of a rupture a surface with two-unitarea forms the work of cohesion is as follows

119882119896 = 2120590 (4)

To characterize the wetting process the spreading coeffi-cient 119878 is used which is taken as the difference between thework of adhesion119882119886 and the work of cohesion119882119896 For thecomplete wetting 119878 rarr 0

119878 = 119882119886 minus119882119896 = 120590119897 times (cos 120579 minus 1) (5)

The relationship between the work of adhesion andcohesion can be expressed through a relative value a relativeadhesion work of liquid 119885119886

119885119886 =119882119886

119882119896 (6)

If 119882119886 and 119882119896 are expressed in terms of the quantitiesdefined in (3) and (4) then

119885119886 =1 + cos 1205792 (7)

To study the dynamic viscosity (according to ASTMD4402) of modified bitumen samples dynamic tests werecarried out using Rheotest RN 41 We obtained the depen-dence of dynamic viscosity (mPasdots) from temperature (∘C)at a constant shear rate (100 sminus1) The measurements werecarried out in the following way first the measuring systemldquocone-platerdquo was heated to 125∘b on which bitumen sampleswere laid (original bitumen and the bitumenmodified by 0608 10 and 12 wt of PFM resp) then the measurementswere taken along with cooling of the samples In order tostudy the thixotropic properties of the samples immediately

6 Advances in Materials Science and Engineering

Table 5 Physical-chemical characteristics of the PFM

Number The name of indicators The meaning Testing method(1) Appearance The viscous honey-like mass Visually(2) Colour From light yellow to dark brown Visually(3) Smell Weak characteristic Organoleptic(4) Density at 20∘C gcm3 09538 GOST 3900-85(5) Kinematic viscosity at 100∘C mm2s 1396 GOST 33-2000

(a) (b)

Figure 4 The results of the impact of adhesion additive on the adhesion between bitumen and aggregates (a) the original bitumen 6090without additive (b) bitumen with 1 wt of PFM

after direct measurements the viscosity was measured in theopposite direction with a decrease in the shear rate from 1000to 1 sminus1 at temperatures of 80ndash120∘C

The properties of binders such as softening temperature(EN 1427 ASTMD36 AASHTOT53) brittleness temperatureaccording to Fraas (ie the Fraass Breaking Point EN 12593-2013) penetration (EN 1426 ASTM D5 AASHTO T49)ductility (EN 133981358713589 ASTM D 113 AASHTO T51) and the change of the bitumen softening temperatureafter heating were determined according to GOST 22245-90 ldquoViscous petroleum road bitumenrdquo [24] First bitumensamples are heated in the drying oven at a temperature of163∘C for 5 hours in accordance with GOST 18180-72 [25]after which the softening temperature is determined Densityat 20∘C and kinematic viscosity at 100∘C were determined inaccordancewithGOST 3900-85 [26] andGOST 33-2000 [27]respectively

The thermal stability test of modified bitumen was carriedout at temperatures of 163 180 and 200∘C and a heatingduration of 25 hours (max) with the use of stone materialsof basic and acidic nature The temperature of 163∘C isspecified by GOST 18180-72 [25] and ASTM D 2872 [28]The temperatures of 180 and 200∘C were chosen upon therecommendations of road constructing organizations Themodified bitumen that was under a thermal exposure wassampled every 5 hours and then the adhesion test wasconducted according to the above-mentioned techniqueBitumen binder can be stored at bitumen storage where it isconstantly heated to keep fluidness formaximum 24 h beforeit is directed to an asphalt concrete mixing vessel For thatreason the maximum duration of heating (25 h) was chosenthat exceeds possible storage period

Pilot-scale tests were also conducted as well as thetechnical inspection of asphalt concrete mixtures the resultsof the latest were compared with the GOST 9128-2009 [29]requirements

3 Results and Discussion

31 Comparative Study of the Obtained Additives and TheirEffect on Bitumen Properties The features and advantages ofthe PFM compared to adhesive ldquoAmidanrdquo are the followinghigh adhesion (at high temperatures aswell) thermal stabilityat 250ndash270∘C within 4 hours (compared to the values of120ndash175∘C) high flash point and high processability thepossibility of dosing directly into the bitumen that is outflowof the oxidizing columnwith a temperature up to 280∘C PFMincludes both polymer and adhesive characteristics whichaffects the production costs Despite the fact that additive isdoped in small amounts (up to 08ndash10 wt) they also affectthe physical-chemical properties of the finalACThe speciallydesigned spacerrsquos structure enables starting of secondarypolymerization processes taking place between asphaltenicand resinous compounds in bitumen media

Physical-chemical characteristics of the synthesized PFMare presented in Table 5

Research of the polyfunctional modifier influence onthe adhesion between bitumen and the aggregates (mineralmaterial) was carried on the above-mentioned sample of6090 bitumen of OAO TAIF-NK production with thecharacteristics shown in Table 6 As it can be seen fromthe data in Table 6 proposed compounds added at amountsof 05ndash10 have improved adhesion between bitumen andthe mineral filler surface corresponding to five points inaccordance with GOST 12801-98

Pictures taken after the performed adhesion test arepresented on Figure 4 When a mineral material is coated

Advances in Materials Science and Engineering 7

Table6Re

sults

oftheq

ualitytests

ofbitumen

mod

ified

with

theu

seof

synthesiz

edcompo

unds

Com

poun

dDosage

Softe

ning

temperature

∘b

Penetration

01m

mDuctilitycm

Adhesio

npo

ints

Brittlenesstemperature

byFraas∘b

Thec

hangeo

fbitu

men

softe

ning

pointafte

rheatin

g(Δ119905 soft)∘b

25∘b

0∘b

25∘b

0∘b

Orig

inalbitumen

mdash497

6722

8455

2minus23

50

Com

poun

d(IIIa

)(119899=1)

01

495

6722

8455

3minus23

mdash025

493

7023

8455

4minus24

30

05

4972

2484

55

5minus26

21

10488

7525

8556

5minus27

1015

485

7826

8657

5minus27

mdash

Com

poun

d(III3)

(119899=2)

01

495

6722

8455

3minus23

mdash025

493

6722

8455

4minus24

32

05

4968

2384

55

5minus26

20

10488

6923

8556

5minus27

1015

485

7024

8657

5minus27

mdash

Com

poun

d(IIIk)

(119899=3)

01

496

6722

8455

3minus23

mdash025

495

6722

8455

4minus24

35

05

493

6823

8455

5minus26

23

10490

6923

8556

5minus27

1015

486

7024

8657

5minus27

mdash

ldquoAmidanrdquo

01

45120

3mdash

025

45120

470

05

45120

565

1046

115

560

1546

115

550

8 Advances in Materials Science and Engineering

Table 7 Surface tension of the bitumen samples

Bitumen samples Original PFM content wt06 08 10 12

Average value 120590119897 mNm 3304 3138 3134 3146 3142

with the original bitumen (ie without modifying additives)the binder film is persistent on the area of less than 50 ofstonesrsquo surface corresponding to 2 points Addition of 1 wtofmodifier leads to complete coverage of themineralmaterialsurface corresponding to 5 points

The use of PFM improves the thermal stability of bitumen(Table 6) Thus bitumen with PFM additive amounts of09ndash10 wt has lowΔ119905soft equal to 1

∘Cwhile for the bitumenwith ldquoAmidanrdquo Δ119905soft equals 6∘C In addition there has beenimprovement in the penetration which indicates the bitumenbinder improved plasticity

The test results indicate the fact that the increase in thecontent of adhesive additives in the range from 0 to 15 wtleads to increase of penetration values (at 25∘C) namely from67 to 78 (01mm) respectively (Table 6)

The results of adhesive additive ldquoAmidanrdquo testing (Table 6)indicate deterioration of the bitumen properties Though theadhesion is equal for both adhesives ldquoAmidanrdquo acts as adiluting agent leading to increase in the penetration valueThe latest would lead to fractionation (ie delamination)of the binder in the process of its application The changesof ldquoAmidanrdquo-modified bitumen softening temperatures afterheating are too high do not meet the standard requirementsand mean low stability of the binder For that reason no fur-ther tests were carried out for bitumen containing ldquoAmidanrdquo

Regarding the brittleness temperature determinedaccording to Fraas (the Fraass Breaking Point) it indicatesthe lower temperature at which the bitumen loses viscoplasticproperties and as a consequence becomes brittle It is knownthat the lower the brittle point the wider the temperaturerange in which the bitumen is in the viscoplastic state andtherefore the better its physical-mechanical characteristicsIn this case the additive doping allows reducing the brittlepoint and consequently providing expansion of ductilitytemperature range Apart from the above-mentionedadvantages it should be noted that the compounds aresuperior to ldquoAmidanrdquo in adhesion at high temperaturesThus the modified bitumen with additives amount of09ndash10 wt shows high adhesion to sand (5 points) afterthermal exposure at temperatures of 220ndash240∘C for 12 hoursIt should be noted that the bitumen with the same amountsldquoAmidanrdquo exhibits much lower thermal stability providingsimilar adhesion only at temperatures above 170∘C

32 Contact Angle Measurements and Adhesion Work Calcu-lation Figure 5 shows the dependence of the glass surfacewetting contact angle on the content of the additive It isestablished that bitumen does not wet the glass becausecos 120579 has negative values Doping the proposed additive into

bitumen results in a slight increase in wetting ability anextremum is observed with an additive content of 08

Figure 6 shows the dependence of the aggregates wettingcontact angle on the content of the additive It can be seen thatthe presence of an additive significantly changes the wettingof the mineral substrate by the modified bitumen a wettinginversion is observed that is cos 120579 increases with increasingcontent of the additive and acquires positive values We notethat in the case of the surface of mineral materials anextremum is also observed with an additive content of 08by weight

Surface tension measurements results are presented inTable 7

The data in Table 7 indicates that the surface tensiondecreases with the addition of the additive This agrees withthe data of [30] that the surface tension at the bitumen-solidinterface decreases with increasing of surfactants contentSurface tension in combinationwith adhesion properties pro-vides information of the strength of the bitumen adherence tomineral material

The calculated values of the above-mentioned charac-teristics of the ldquoaggregates-organic binderrdquo system surfaceproperties that is wetting energy adhesion work cohesionwork spreading coefficient and relative adhesion work arepresented in Table 8

The analysis of the obtained data shows that the PFMbeing adsorbed at the interface promotes better wetting ofthe aggregates surface with bitumen In this case the contactangle 120579 decreases the spreading coefficient and relativeadhesion work increase reaching a peak when an additivecontent is 08 wt and cohesion work is reduced

The value of119885119886 approaches 1 Consequently the adhesionforces between bitumen and mineral materials approximatein magnitude to the binding forces of the bitumenmoleculesThis contributes to the formation of a material with ahomogeneous defect-free structure

33 Component Composition and Dispersity of the BitumenInformation on the component composition can play animportant role in studying the changes occurring as a resultof bitumen modification (Table 9) Thus when introducingthe developed additive into the initial bitumen in an amountof about 1 by weight mainly the content of saturates inthe direction of decrease and asphaltenes in the direction ofincrease is changing In this case the relative and absolutechanges of the remaining groups of components are insignif-icant

The sequence of hydrocarbon group transitions in thiscase can be delineated as follows [31]

Aromatics (PCA) 997888rarr aromatics (MCA)larr997888 saturates 997888rarr asphaltenes (8)

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

4 Advances in Materials Science and Engineering

Table 1 Physicochemical characteristics of N-acylated bisimidazolines derivatives (IIIandashIIIk)

CompoundElement analysisfoundcalculated

Basicity of amidesml 01 N HClO4gfoundcalculatedC N

(III1) 78577864 729740 10491056

(III3) 78417851 663670 15851594

(IIIk) 78327843 619628 19181921

100

80

60

40

20

0

1600 1400 1200 1000 800

(a)

100

80

60

40

20

0

1600 1400 1200 1000 800

(b)

Figure 3 IR spectra of the additives (a) and the original bitumen BND 6090 (TAIF-NK) (b)

Absorption bands with the following wave numbers wereobserved in the IR spectra of the obtained compounds (Fig-ure 3(a)) 120592C=N = 1600ndash1630 cmminus1 indicating the presenceof imidazoline cycles 120592C= = 1740ndash1745 cmminus1 120592ndashN(CO)R= 1660 cmminus1 and 120592CN = 1260ndash1300 cmminus1 can be related toalkanoylamide structures 120575(CH2)x = 720 cm

minus1 ndash correspondsto pendular oscillation of alkylene structure in a chain [21]Wide absorption bands at 1600 cmminus1 in FTIR spectra of theoriginal bitumen (Figure 3(b)) stand for the 120592CH bond inaromatic ring sharp absorption bands with high intensity at1440 and 1460 cmminus1 correspond to stretch vibration of ndashCH2ndashstructure fragment in long chains confirming high contentof paraffin waxes absorption band at 1375 cmminus1 is related tomethyl groups

22 Bitumen Modification and Performance Properties Analy-sis Investigation of the effect of the synthesized compoundson the adhesion between bitumen and the mineral materialwas carried out by the use of example of oxidized bitumen of6090 penetration grade (BND 6090 (the mark of bitumenin Russia means ldquopetroleum bitumen for roadsrdquo)) that wasproduced in TAIF-NK PSC with the following group chem-ical composition wt 2262 of saturates (including 102 of paraffin waxes) 1514 of aromatics 4026 of resins 2198 ofasphaltenes

The bitumen modification process was carried out asfollows

(1) The BND was heated in a metal vessel to the tem-perature of 80∘C with the use of stirring mechanismkept under thermostatic control for 20min to obtainhomogeneous diluted substance with homogeneousdistribution of components

(2) The BND was gradually heated to the temperature of120ndash130∘C at which it was kept for 20min

(3) Obtained PFM substances were injected into theheated bitumen and stirred for 20ndash30min to ensurehomogenous dispersion of the PFM in bitumenmedia

The adhesion between bitumen and aggregates (mineralmaterial) testing was conducted in accordance with GOST(GOST Russian state standard) 12801-98 [22] the essence ofwhich is to determine the ability of the viscous bitumen thatis precoated on the surface of mineral material to persist onit while being exposed by water The quality of the adhesionassessment was rated according to Table 2

The ability of bitumen to coat aggregates was evaluatedbased on contact angle measurement Original BND 6090and modified by PFM in amount of 06 08 10 and 12 wtwere taken The contact angle of wetting was determinedon two surfaces on glass which is the standard of thepolar surface as well as mineral rocks of various genesis(dolomitized limestone consisting of 90 dolomite and 10calcite) from ldquoBianca gravel factoryrdquo chemical compositionsof which are presented in Tables 3-4 Pervouralsk aggregateswere considered to be of ldquoacidicrdquo nature Bianca ndash is of ldquobasicrdquonature

Measurements were carried out using cathetometer KM-8 by direct measurement of the base and height of the dropwith subsequent calculation [23] The cosine of the contactangle of the drop is calculated by the formula

cos 120579 = 1199032 minus ℎ2

1199032 + ℎ2 (1)

where 119903 = 1198712 is the droplet radius 119871 is the droplet baseand ℎ is the droplet height With the help of a cathetometerthe contact angles of the taken aggregates wetting by bitumen

Advances in Materials Science and Engineering 5

Table 2 Evaluation of grip (adhesion)

Feature of the bitumen film on the surface of crushed stone Evaluation of gripBinder film is completely retained on the surface local decreasing of the thickness of a film can be observed Excellent (five points)Binder film is completely retained on the surface but is partially separated from the sharp corners and edges Good (four points)Binder film is retained on over 50 of crushed stone surface Satisfactory (three points)Binder film is retained on less than 50 of crushed stone surface On the exposed surface individual bitumendroplets are observed Poor (two points)

Table 3 Chemical composition of the ldquoPervouralsk mine managementrdquo gravel

Content in terms of dry matter wtSiO2 TiO2 Al2O3 Fe2O3 FeO CaO MgO MnO K2O Na2O V2O5 P2O5 S221 327 117 272 169 89 90 023 02 014 04 001 003

Table 4 Chemical composition of the ldquoBianca gravel factoryrdquo gravel

Content in terms of dry matter wtSiO2 Fe2O3 CaO MgO Al2O3 SO3 ]3щ CaCO3 MgCO333 07 209 119 08 03 372 249

binder samples were determined The drop of bitumen (ofthe same size and mass as far as possible) was laid onto thesurface of a substrate at a bitumen temperature of 130∘CAs the drop of bitumen cools instantly as soon as it reachesthe cold substrate surface the samples of the stone materialswere heated to 40∘C which practically did not change thesurface properties of the rock but retained the liquid stateof the bitumen for a sufficient time The equilibrium valueof the wetting contact angle was determined on the basis ofthe kinetic curves The wetting angle was measured twiceimmediately after the dropping of the bitumen and after 1minute necessary to achieve equilibrium wetting angle Thelatest value was taken into account

It is known that adhesion of bitumen tomineral materialsis the work required to separate the bitumen layer from thesematerials In order to determine the work of adhesion (aquantitative measure) between aggregates and bitumen wemeasured the surface tension of bitumen in the presence ofthe PFM Surface tension at the interface between binder andair phases (120590BA) is the most important factor determining theintensity of wetting of amineral substrate by bitumen Surfacetension measurements were carried out at a temperature of25∘Cusing EasyDyne S K20S tensiometer (KRUSS) by theDuNui ring method Bitumen samples were dissolved in tolueneat a mass ratio of toluene bitumen equal to 1 15

Based on the obtained values of 120579 and 120590 the wettingenergy or the adhesive stress was calculated

119882119890 = 120590 times cos 120579 (2)

The work of adhesion was calculated using Young-Dupreequation

119882119886 = 120590 times (1 + cos 120579) (3)

The work of cohesion was calculated to assess the interac-tion strength between the bitumen components The work of

cohesion is determined by the expenditure of energy on thereversible rupture of the body over a section equal to unit ofarea Since as a result of a rupture a surface with two-unitarea forms the work of cohesion is as follows

119882119896 = 2120590 (4)

To characterize the wetting process the spreading coeffi-cient 119878 is used which is taken as the difference between thework of adhesion119882119886 and the work of cohesion119882119896 For thecomplete wetting 119878 rarr 0

119878 = 119882119886 minus119882119896 = 120590119897 times (cos 120579 minus 1) (5)

The relationship between the work of adhesion andcohesion can be expressed through a relative value a relativeadhesion work of liquid 119885119886

119885119886 =119882119886

119882119896 (6)

If 119882119886 and 119882119896 are expressed in terms of the quantitiesdefined in (3) and (4) then

119885119886 =1 + cos 1205792 (7)

To study the dynamic viscosity (according to ASTMD4402) of modified bitumen samples dynamic tests werecarried out using Rheotest RN 41 We obtained the depen-dence of dynamic viscosity (mPasdots) from temperature (∘C)at a constant shear rate (100 sminus1) The measurements werecarried out in the following way first the measuring systemldquocone-platerdquo was heated to 125∘b on which bitumen sampleswere laid (original bitumen and the bitumenmodified by 0608 10 and 12 wt of PFM resp) then the measurementswere taken along with cooling of the samples In order tostudy the thixotropic properties of the samples immediately

6 Advances in Materials Science and Engineering

Table 5 Physical-chemical characteristics of the PFM

Number The name of indicators The meaning Testing method(1) Appearance The viscous honey-like mass Visually(2) Colour From light yellow to dark brown Visually(3) Smell Weak characteristic Organoleptic(4) Density at 20∘C gcm3 09538 GOST 3900-85(5) Kinematic viscosity at 100∘C mm2s 1396 GOST 33-2000

(a) (b)

Figure 4 The results of the impact of adhesion additive on the adhesion between bitumen and aggregates (a) the original bitumen 6090without additive (b) bitumen with 1 wt of PFM

after direct measurements the viscosity was measured in theopposite direction with a decrease in the shear rate from 1000to 1 sminus1 at temperatures of 80ndash120∘C

The properties of binders such as softening temperature(EN 1427 ASTMD36 AASHTOT53) brittleness temperatureaccording to Fraas (ie the Fraass Breaking Point EN 12593-2013) penetration (EN 1426 ASTM D5 AASHTO T49)ductility (EN 133981358713589 ASTM D 113 AASHTO T51) and the change of the bitumen softening temperatureafter heating were determined according to GOST 22245-90 ldquoViscous petroleum road bitumenrdquo [24] First bitumensamples are heated in the drying oven at a temperature of163∘C for 5 hours in accordance with GOST 18180-72 [25]after which the softening temperature is determined Densityat 20∘C and kinematic viscosity at 100∘C were determined inaccordancewithGOST 3900-85 [26] andGOST 33-2000 [27]respectively

The thermal stability test of modified bitumen was carriedout at temperatures of 163 180 and 200∘C and a heatingduration of 25 hours (max) with the use of stone materialsof basic and acidic nature The temperature of 163∘C isspecified by GOST 18180-72 [25] and ASTM D 2872 [28]The temperatures of 180 and 200∘C were chosen upon therecommendations of road constructing organizations Themodified bitumen that was under a thermal exposure wassampled every 5 hours and then the adhesion test wasconducted according to the above-mentioned techniqueBitumen binder can be stored at bitumen storage where it isconstantly heated to keep fluidness formaximum 24 h beforeit is directed to an asphalt concrete mixing vessel For thatreason the maximum duration of heating (25 h) was chosenthat exceeds possible storage period

Pilot-scale tests were also conducted as well as thetechnical inspection of asphalt concrete mixtures the resultsof the latest were compared with the GOST 9128-2009 [29]requirements

3 Results and Discussion

31 Comparative Study of the Obtained Additives and TheirEffect on Bitumen Properties The features and advantages ofthe PFM compared to adhesive ldquoAmidanrdquo are the followinghigh adhesion (at high temperatures aswell) thermal stabilityat 250ndash270∘C within 4 hours (compared to the values of120ndash175∘C) high flash point and high processability thepossibility of dosing directly into the bitumen that is outflowof the oxidizing columnwith a temperature up to 280∘C PFMincludes both polymer and adhesive characteristics whichaffects the production costs Despite the fact that additive isdoped in small amounts (up to 08ndash10 wt) they also affectthe physical-chemical properties of the finalACThe speciallydesigned spacerrsquos structure enables starting of secondarypolymerization processes taking place between asphaltenicand resinous compounds in bitumen media

Physical-chemical characteristics of the synthesized PFMare presented in Table 5

Research of the polyfunctional modifier influence onthe adhesion between bitumen and the aggregates (mineralmaterial) was carried on the above-mentioned sample of6090 bitumen of OAO TAIF-NK production with thecharacteristics shown in Table 6 As it can be seen fromthe data in Table 6 proposed compounds added at amountsof 05ndash10 have improved adhesion between bitumen andthe mineral filler surface corresponding to five points inaccordance with GOST 12801-98

Pictures taken after the performed adhesion test arepresented on Figure 4 When a mineral material is coated

Advances in Materials Science and Engineering 7

Table6Re

sults

oftheq

ualitytests

ofbitumen

mod

ified

with

theu

seof

synthesiz

edcompo

unds

Com

poun

dDosage

Softe

ning

temperature

∘b

Penetration

01m

mDuctilitycm

Adhesio

npo

ints

Brittlenesstemperature

byFraas∘b

Thec

hangeo

fbitu

men

softe

ning

pointafte

rheatin

g(Δ119905 soft)∘b

25∘b

0∘b

25∘b

0∘b

Orig

inalbitumen

mdash497

6722

8455

2minus23

50

Com

poun

d(IIIa

)(119899=1)

01

495

6722

8455

3minus23

mdash025

493

7023

8455

4minus24

30

05

4972

2484

55

5minus26

21

10488

7525

8556

5minus27

1015

485

7826

8657

5minus27

mdash

Com

poun

d(III3)

(119899=2)

01

495

6722

8455

3minus23

mdash025

493

6722

8455

4minus24

32

05

4968

2384

55

5minus26

20

10488

6923

8556

5minus27

1015

485

7024

8657

5minus27

mdash

Com

poun

d(IIIk)

(119899=3)

01

496

6722

8455

3minus23

mdash025

495

6722

8455

4minus24

35

05

493

6823

8455

5minus26

23

10490

6923

8556

5minus27

1015

486

7024

8657

5minus27

mdash

ldquoAmidanrdquo

01

45120

3mdash

025

45120

470

05

45120

565

1046

115

560

1546

115

550

8 Advances in Materials Science and Engineering

Table 7 Surface tension of the bitumen samples

Bitumen samples Original PFM content wt06 08 10 12

Average value 120590119897 mNm 3304 3138 3134 3146 3142

with the original bitumen (ie without modifying additives)the binder film is persistent on the area of less than 50 ofstonesrsquo surface corresponding to 2 points Addition of 1 wtofmodifier leads to complete coverage of themineralmaterialsurface corresponding to 5 points

The use of PFM improves the thermal stability of bitumen(Table 6) Thus bitumen with PFM additive amounts of09ndash10 wt has lowΔ119905soft equal to 1

∘Cwhile for the bitumenwith ldquoAmidanrdquo Δ119905soft equals 6∘C In addition there has beenimprovement in the penetration which indicates the bitumenbinder improved plasticity

The test results indicate the fact that the increase in thecontent of adhesive additives in the range from 0 to 15 wtleads to increase of penetration values (at 25∘C) namely from67 to 78 (01mm) respectively (Table 6)

The results of adhesive additive ldquoAmidanrdquo testing (Table 6)indicate deterioration of the bitumen properties Though theadhesion is equal for both adhesives ldquoAmidanrdquo acts as adiluting agent leading to increase in the penetration valueThe latest would lead to fractionation (ie delamination)of the binder in the process of its application The changesof ldquoAmidanrdquo-modified bitumen softening temperatures afterheating are too high do not meet the standard requirementsand mean low stability of the binder For that reason no fur-ther tests were carried out for bitumen containing ldquoAmidanrdquo

Regarding the brittleness temperature determinedaccording to Fraas (the Fraass Breaking Point) it indicatesthe lower temperature at which the bitumen loses viscoplasticproperties and as a consequence becomes brittle It is knownthat the lower the brittle point the wider the temperaturerange in which the bitumen is in the viscoplastic state andtherefore the better its physical-mechanical characteristicsIn this case the additive doping allows reducing the brittlepoint and consequently providing expansion of ductilitytemperature range Apart from the above-mentionedadvantages it should be noted that the compounds aresuperior to ldquoAmidanrdquo in adhesion at high temperaturesThus the modified bitumen with additives amount of09ndash10 wt shows high adhesion to sand (5 points) afterthermal exposure at temperatures of 220ndash240∘C for 12 hoursIt should be noted that the bitumen with the same amountsldquoAmidanrdquo exhibits much lower thermal stability providingsimilar adhesion only at temperatures above 170∘C

32 Contact Angle Measurements and Adhesion Work Calcu-lation Figure 5 shows the dependence of the glass surfacewetting contact angle on the content of the additive It isestablished that bitumen does not wet the glass becausecos 120579 has negative values Doping the proposed additive into

bitumen results in a slight increase in wetting ability anextremum is observed with an additive content of 08

Figure 6 shows the dependence of the aggregates wettingcontact angle on the content of the additive It can be seen thatthe presence of an additive significantly changes the wettingof the mineral substrate by the modified bitumen a wettinginversion is observed that is cos 120579 increases with increasingcontent of the additive and acquires positive values We notethat in the case of the surface of mineral materials anextremum is also observed with an additive content of 08by weight

Surface tension measurements results are presented inTable 7

The data in Table 7 indicates that the surface tensiondecreases with the addition of the additive This agrees withthe data of [30] that the surface tension at the bitumen-solidinterface decreases with increasing of surfactants contentSurface tension in combinationwith adhesion properties pro-vides information of the strength of the bitumen adherence tomineral material

The calculated values of the above-mentioned charac-teristics of the ldquoaggregates-organic binderrdquo system surfaceproperties that is wetting energy adhesion work cohesionwork spreading coefficient and relative adhesion work arepresented in Table 8

The analysis of the obtained data shows that the PFMbeing adsorbed at the interface promotes better wetting ofthe aggregates surface with bitumen In this case the contactangle 120579 decreases the spreading coefficient and relativeadhesion work increase reaching a peak when an additivecontent is 08 wt and cohesion work is reduced

The value of119885119886 approaches 1 Consequently the adhesionforces between bitumen and mineral materials approximatein magnitude to the binding forces of the bitumenmoleculesThis contributes to the formation of a material with ahomogeneous defect-free structure

33 Component Composition and Dispersity of the BitumenInformation on the component composition can play animportant role in studying the changes occurring as a resultof bitumen modification (Table 9) Thus when introducingthe developed additive into the initial bitumen in an amountof about 1 by weight mainly the content of saturates inthe direction of decrease and asphaltenes in the direction ofincrease is changing In this case the relative and absolutechanges of the remaining groups of components are insignif-icant

The sequence of hydrocarbon group transitions in thiscase can be delineated as follows [31]

Aromatics (PCA) 997888rarr aromatics (MCA)larr997888 saturates 997888rarr asphaltenes (8)

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

Advances in Materials Science and Engineering 5

Table 2 Evaluation of grip (adhesion)

Feature of the bitumen film on the surface of crushed stone Evaluation of gripBinder film is completely retained on the surface local decreasing of the thickness of a film can be observed Excellent (five points)Binder film is completely retained on the surface but is partially separated from the sharp corners and edges Good (four points)Binder film is retained on over 50 of crushed stone surface Satisfactory (three points)Binder film is retained on less than 50 of crushed stone surface On the exposed surface individual bitumendroplets are observed Poor (two points)

Table 3 Chemical composition of the ldquoPervouralsk mine managementrdquo gravel

Content in terms of dry matter wtSiO2 TiO2 Al2O3 Fe2O3 FeO CaO MgO MnO K2O Na2O V2O5 P2O5 S221 327 117 272 169 89 90 023 02 014 04 001 003

Table 4 Chemical composition of the ldquoBianca gravel factoryrdquo gravel

Content in terms of dry matter wtSiO2 Fe2O3 CaO MgO Al2O3 SO3 ]3щ CaCO3 MgCO333 07 209 119 08 03 372 249

binder samples were determined The drop of bitumen (ofthe same size and mass as far as possible) was laid onto thesurface of a substrate at a bitumen temperature of 130∘CAs the drop of bitumen cools instantly as soon as it reachesthe cold substrate surface the samples of the stone materialswere heated to 40∘C which practically did not change thesurface properties of the rock but retained the liquid stateof the bitumen for a sufficient time The equilibrium valueof the wetting contact angle was determined on the basis ofthe kinetic curves The wetting angle was measured twiceimmediately after the dropping of the bitumen and after 1minute necessary to achieve equilibrium wetting angle Thelatest value was taken into account

It is known that adhesion of bitumen tomineral materialsis the work required to separate the bitumen layer from thesematerials In order to determine the work of adhesion (aquantitative measure) between aggregates and bitumen wemeasured the surface tension of bitumen in the presence ofthe PFM Surface tension at the interface between binder andair phases (120590BA) is the most important factor determining theintensity of wetting of amineral substrate by bitumen Surfacetension measurements were carried out at a temperature of25∘Cusing EasyDyne S K20S tensiometer (KRUSS) by theDuNui ring method Bitumen samples were dissolved in tolueneat a mass ratio of toluene bitumen equal to 1 15

Based on the obtained values of 120579 and 120590 the wettingenergy or the adhesive stress was calculated

119882119890 = 120590 times cos 120579 (2)

The work of adhesion was calculated using Young-Dupreequation

119882119886 = 120590 times (1 + cos 120579) (3)

The work of cohesion was calculated to assess the interac-tion strength between the bitumen components The work of

cohesion is determined by the expenditure of energy on thereversible rupture of the body over a section equal to unit ofarea Since as a result of a rupture a surface with two-unitarea forms the work of cohesion is as follows

119882119896 = 2120590 (4)

To characterize the wetting process the spreading coeffi-cient 119878 is used which is taken as the difference between thework of adhesion119882119886 and the work of cohesion119882119896 For thecomplete wetting 119878 rarr 0

119878 = 119882119886 minus119882119896 = 120590119897 times (cos 120579 minus 1) (5)

The relationship between the work of adhesion andcohesion can be expressed through a relative value a relativeadhesion work of liquid 119885119886

119885119886 =119882119886

119882119896 (6)

If 119882119886 and 119882119896 are expressed in terms of the quantitiesdefined in (3) and (4) then

119885119886 =1 + cos 1205792 (7)

To study the dynamic viscosity (according to ASTMD4402) of modified bitumen samples dynamic tests werecarried out using Rheotest RN 41 We obtained the depen-dence of dynamic viscosity (mPasdots) from temperature (∘C)at a constant shear rate (100 sminus1) The measurements werecarried out in the following way first the measuring systemldquocone-platerdquo was heated to 125∘b on which bitumen sampleswere laid (original bitumen and the bitumenmodified by 0608 10 and 12 wt of PFM resp) then the measurementswere taken along with cooling of the samples In order tostudy the thixotropic properties of the samples immediately

6 Advances in Materials Science and Engineering

Table 5 Physical-chemical characteristics of the PFM

Number The name of indicators The meaning Testing method(1) Appearance The viscous honey-like mass Visually(2) Colour From light yellow to dark brown Visually(3) Smell Weak characteristic Organoleptic(4) Density at 20∘C gcm3 09538 GOST 3900-85(5) Kinematic viscosity at 100∘C mm2s 1396 GOST 33-2000

(a) (b)

Figure 4 The results of the impact of adhesion additive on the adhesion between bitumen and aggregates (a) the original bitumen 6090without additive (b) bitumen with 1 wt of PFM

after direct measurements the viscosity was measured in theopposite direction with a decrease in the shear rate from 1000to 1 sminus1 at temperatures of 80ndash120∘C

The properties of binders such as softening temperature(EN 1427 ASTMD36 AASHTOT53) brittleness temperatureaccording to Fraas (ie the Fraass Breaking Point EN 12593-2013) penetration (EN 1426 ASTM D5 AASHTO T49)ductility (EN 133981358713589 ASTM D 113 AASHTO T51) and the change of the bitumen softening temperatureafter heating were determined according to GOST 22245-90 ldquoViscous petroleum road bitumenrdquo [24] First bitumensamples are heated in the drying oven at a temperature of163∘C for 5 hours in accordance with GOST 18180-72 [25]after which the softening temperature is determined Densityat 20∘C and kinematic viscosity at 100∘C were determined inaccordancewithGOST 3900-85 [26] andGOST 33-2000 [27]respectively

The thermal stability test of modified bitumen was carriedout at temperatures of 163 180 and 200∘C and a heatingduration of 25 hours (max) with the use of stone materialsof basic and acidic nature The temperature of 163∘C isspecified by GOST 18180-72 [25] and ASTM D 2872 [28]The temperatures of 180 and 200∘C were chosen upon therecommendations of road constructing organizations Themodified bitumen that was under a thermal exposure wassampled every 5 hours and then the adhesion test wasconducted according to the above-mentioned techniqueBitumen binder can be stored at bitumen storage where it isconstantly heated to keep fluidness formaximum 24 h beforeit is directed to an asphalt concrete mixing vessel For thatreason the maximum duration of heating (25 h) was chosenthat exceeds possible storage period

Pilot-scale tests were also conducted as well as thetechnical inspection of asphalt concrete mixtures the resultsof the latest were compared with the GOST 9128-2009 [29]requirements

3 Results and Discussion

31 Comparative Study of the Obtained Additives and TheirEffect on Bitumen Properties The features and advantages ofthe PFM compared to adhesive ldquoAmidanrdquo are the followinghigh adhesion (at high temperatures aswell) thermal stabilityat 250ndash270∘C within 4 hours (compared to the values of120ndash175∘C) high flash point and high processability thepossibility of dosing directly into the bitumen that is outflowof the oxidizing columnwith a temperature up to 280∘C PFMincludes both polymer and adhesive characteristics whichaffects the production costs Despite the fact that additive isdoped in small amounts (up to 08ndash10 wt) they also affectthe physical-chemical properties of the finalACThe speciallydesigned spacerrsquos structure enables starting of secondarypolymerization processes taking place between asphaltenicand resinous compounds in bitumen media

Physical-chemical characteristics of the synthesized PFMare presented in Table 5

Research of the polyfunctional modifier influence onthe adhesion between bitumen and the aggregates (mineralmaterial) was carried on the above-mentioned sample of6090 bitumen of OAO TAIF-NK production with thecharacteristics shown in Table 6 As it can be seen fromthe data in Table 6 proposed compounds added at amountsof 05ndash10 have improved adhesion between bitumen andthe mineral filler surface corresponding to five points inaccordance with GOST 12801-98

Pictures taken after the performed adhesion test arepresented on Figure 4 When a mineral material is coated

Advances in Materials Science and Engineering 7

Table6Re

sults

oftheq

ualitytests

ofbitumen

mod

ified

with

theu

seof

synthesiz

edcompo

unds

Com

poun

dDosage

Softe

ning

temperature

∘b

Penetration

01m

mDuctilitycm

Adhesio

npo

ints

Brittlenesstemperature

byFraas∘b

Thec

hangeo

fbitu

men

softe

ning

pointafte

rheatin

g(Δ119905 soft)∘b

25∘b

0∘b

25∘b

0∘b

Orig

inalbitumen

mdash497

6722

8455

2minus23

50

Com

poun

d(IIIa

)(119899=1)

01

495

6722

8455

3minus23

mdash025

493

7023

8455

4minus24

30

05

4972

2484

55

5minus26

21

10488

7525

8556

5minus27

1015

485

7826

8657

5minus27

mdash

Com

poun

d(III3)

(119899=2)

01

495

6722

8455

3minus23

mdash025

493

6722

8455

4minus24

32

05

4968

2384

55

5minus26

20

10488

6923

8556

5minus27

1015

485

7024

8657

5minus27

mdash

Com

poun

d(IIIk)

(119899=3)

01

496

6722

8455

3minus23

mdash025

495

6722

8455

4minus24

35

05

493

6823

8455

5minus26

23

10490

6923

8556

5minus27

1015

486

7024

8657

5minus27

mdash

ldquoAmidanrdquo

01

45120

3mdash

025

45120

470

05

45120

565

1046

115

560

1546

115

550

8 Advances in Materials Science and Engineering

Table 7 Surface tension of the bitumen samples

Bitumen samples Original PFM content wt06 08 10 12

Average value 120590119897 mNm 3304 3138 3134 3146 3142

with the original bitumen (ie without modifying additives)the binder film is persistent on the area of less than 50 ofstonesrsquo surface corresponding to 2 points Addition of 1 wtofmodifier leads to complete coverage of themineralmaterialsurface corresponding to 5 points

The use of PFM improves the thermal stability of bitumen(Table 6) Thus bitumen with PFM additive amounts of09ndash10 wt has lowΔ119905soft equal to 1

∘Cwhile for the bitumenwith ldquoAmidanrdquo Δ119905soft equals 6∘C In addition there has beenimprovement in the penetration which indicates the bitumenbinder improved plasticity

The test results indicate the fact that the increase in thecontent of adhesive additives in the range from 0 to 15 wtleads to increase of penetration values (at 25∘C) namely from67 to 78 (01mm) respectively (Table 6)

The results of adhesive additive ldquoAmidanrdquo testing (Table 6)indicate deterioration of the bitumen properties Though theadhesion is equal for both adhesives ldquoAmidanrdquo acts as adiluting agent leading to increase in the penetration valueThe latest would lead to fractionation (ie delamination)of the binder in the process of its application The changesof ldquoAmidanrdquo-modified bitumen softening temperatures afterheating are too high do not meet the standard requirementsand mean low stability of the binder For that reason no fur-ther tests were carried out for bitumen containing ldquoAmidanrdquo

Regarding the brittleness temperature determinedaccording to Fraas (the Fraass Breaking Point) it indicatesthe lower temperature at which the bitumen loses viscoplasticproperties and as a consequence becomes brittle It is knownthat the lower the brittle point the wider the temperaturerange in which the bitumen is in the viscoplastic state andtherefore the better its physical-mechanical characteristicsIn this case the additive doping allows reducing the brittlepoint and consequently providing expansion of ductilitytemperature range Apart from the above-mentionedadvantages it should be noted that the compounds aresuperior to ldquoAmidanrdquo in adhesion at high temperaturesThus the modified bitumen with additives amount of09ndash10 wt shows high adhesion to sand (5 points) afterthermal exposure at temperatures of 220ndash240∘C for 12 hoursIt should be noted that the bitumen with the same amountsldquoAmidanrdquo exhibits much lower thermal stability providingsimilar adhesion only at temperatures above 170∘C

32 Contact Angle Measurements and Adhesion Work Calcu-lation Figure 5 shows the dependence of the glass surfacewetting contact angle on the content of the additive It isestablished that bitumen does not wet the glass becausecos 120579 has negative values Doping the proposed additive into

bitumen results in a slight increase in wetting ability anextremum is observed with an additive content of 08

Figure 6 shows the dependence of the aggregates wettingcontact angle on the content of the additive It can be seen thatthe presence of an additive significantly changes the wettingof the mineral substrate by the modified bitumen a wettinginversion is observed that is cos 120579 increases with increasingcontent of the additive and acquires positive values We notethat in the case of the surface of mineral materials anextremum is also observed with an additive content of 08by weight

Surface tension measurements results are presented inTable 7

The data in Table 7 indicates that the surface tensiondecreases with the addition of the additive This agrees withthe data of [30] that the surface tension at the bitumen-solidinterface decreases with increasing of surfactants contentSurface tension in combinationwith adhesion properties pro-vides information of the strength of the bitumen adherence tomineral material

The calculated values of the above-mentioned charac-teristics of the ldquoaggregates-organic binderrdquo system surfaceproperties that is wetting energy adhesion work cohesionwork spreading coefficient and relative adhesion work arepresented in Table 8

The analysis of the obtained data shows that the PFMbeing adsorbed at the interface promotes better wetting ofthe aggregates surface with bitumen In this case the contactangle 120579 decreases the spreading coefficient and relativeadhesion work increase reaching a peak when an additivecontent is 08 wt and cohesion work is reduced

The value of119885119886 approaches 1 Consequently the adhesionforces between bitumen and mineral materials approximatein magnitude to the binding forces of the bitumenmoleculesThis contributes to the formation of a material with ahomogeneous defect-free structure

33 Component Composition and Dispersity of the BitumenInformation on the component composition can play animportant role in studying the changes occurring as a resultof bitumen modification (Table 9) Thus when introducingthe developed additive into the initial bitumen in an amountof about 1 by weight mainly the content of saturates inthe direction of decrease and asphaltenes in the direction ofincrease is changing In this case the relative and absolutechanges of the remaining groups of components are insignif-icant

The sequence of hydrocarbon group transitions in thiscase can be delineated as follows [31]

Aromatics (PCA) 997888rarr aromatics (MCA)larr997888 saturates 997888rarr asphaltenes (8)

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

6 Advances in Materials Science and Engineering

Table 5 Physical-chemical characteristics of the PFM

Number The name of indicators The meaning Testing method(1) Appearance The viscous honey-like mass Visually(2) Colour From light yellow to dark brown Visually(3) Smell Weak characteristic Organoleptic(4) Density at 20∘C gcm3 09538 GOST 3900-85(5) Kinematic viscosity at 100∘C mm2s 1396 GOST 33-2000

(a) (b)

Figure 4 The results of the impact of adhesion additive on the adhesion between bitumen and aggregates (a) the original bitumen 6090without additive (b) bitumen with 1 wt of PFM

after direct measurements the viscosity was measured in theopposite direction with a decrease in the shear rate from 1000to 1 sminus1 at temperatures of 80ndash120∘C

The properties of binders such as softening temperature(EN 1427 ASTMD36 AASHTOT53) brittleness temperatureaccording to Fraas (ie the Fraass Breaking Point EN 12593-2013) penetration (EN 1426 ASTM D5 AASHTO T49)ductility (EN 133981358713589 ASTM D 113 AASHTO T51) and the change of the bitumen softening temperatureafter heating were determined according to GOST 22245-90 ldquoViscous petroleum road bitumenrdquo [24] First bitumensamples are heated in the drying oven at a temperature of163∘C for 5 hours in accordance with GOST 18180-72 [25]after which the softening temperature is determined Densityat 20∘C and kinematic viscosity at 100∘C were determined inaccordancewithGOST 3900-85 [26] andGOST 33-2000 [27]respectively

The thermal stability test of modified bitumen was carriedout at temperatures of 163 180 and 200∘C and a heatingduration of 25 hours (max) with the use of stone materialsof basic and acidic nature The temperature of 163∘C isspecified by GOST 18180-72 [25] and ASTM D 2872 [28]The temperatures of 180 and 200∘C were chosen upon therecommendations of road constructing organizations Themodified bitumen that was under a thermal exposure wassampled every 5 hours and then the adhesion test wasconducted according to the above-mentioned techniqueBitumen binder can be stored at bitumen storage where it isconstantly heated to keep fluidness formaximum 24 h beforeit is directed to an asphalt concrete mixing vessel For thatreason the maximum duration of heating (25 h) was chosenthat exceeds possible storage period

Pilot-scale tests were also conducted as well as thetechnical inspection of asphalt concrete mixtures the resultsof the latest were compared with the GOST 9128-2009 [29]requirements

3 Results and Discussion

31 Comparative Study of the Obtained Additives and TheirEffect on Bitumen Properties The features and advantages ofthe PFM compared to adhesive ldquoAmidanrdquo are the followinghigh adhesion (at high temperatures aswell) thermal stabilityat 250ndash270∘C within 4 hours (compared to the values of120ndash175∘C) high flash point and high processability thepossibility of dosing directly into the bitumen that is outflowof the oxidizing columnwith a temperature up to 280∘C PFMincludes both polymer and adhesive characteristics whichaffects the production costs Despite the fact that additive isdoped in small amounts (up to 08ndash10 wt) they also affectthe physical-chemical properties of the finalACThe speciallydesigned spacerrsquos structure enables starting of secondarypolymerization processes taking place between asphaltenicand resinous compounds in bitumen media

Physical-chemical characteristics of the synthesized PFMare presented in Table 5

Research of the polyfunctional modifier influence onthe adhesion between bitumen and the aggregates (mineralmaterial) was carried on the above-mentioned sample of6090 bitumen of OAO TAIF-NK production with thecharacteristics shown in Table 6 As it can be seen fromthe data in Table 6 proposed compounds added at amountsof 05ndash10 have improved adhesion between bitumen andthe mineral filler surface corresponding to five points inaccordance with GOST 12801-98

Pictures taken after the performed adhesion test arepresented on Figure 4 When a mineral material is coated

Advances in Materials Science and Engineering 7

Table6Re

sults

oftheq

ualitytests

ofbitumen

mod

ified

with

theu

seof

synthesiz

edcompo

unds

Com

poun

dDosage

Softe

ning

temperature

∘b

Penetration

01m

mDuctilitycm

Adhesio

npo

ints

Brittlenesstemperature

byFraas∘b

Thec

hangeo

fbitu

men

softe

ning

pointafte

rheatin

g(Δ119905 soft)∘b

25∘b

0∘b

25∘b

0∘b

Orig

inalbitumen

mdash497

6722

8455

2minus23

50

Com

poun

d(IIIa

)(119899=1)

01

495

6722

8455

3minus23

mdash025

493

7023

8455

4minus24

30

05

4972

2484

55

5minus26

21

10488

7525

8556

5minus27

1015

485

7826

8657

5minus27

mdash

Com

poun

d(III3)

(119899=2)

01

495

6722

8455

3minus23

mdash025

493

6722

8455

4minus24

32

05

4968

2384

55

5minus26

20

10488

6923

8556

5minus27

1015

485

7024

8657

5minus27

mdash

Com

poun

d(IIIk)

(119899=3)

01

496

6722

8455

3minus23

mdash025

495

6722

8455

4minus24

35

05

493

6823

8455

5minus26

23

10490

6923

8556

5minus27

1015

486

7024

8657

5minus27

mdash

ldquoAmidanrdquo

01

45120

3mdash

025

45120

470

05

45120

565

1046

115

560

1546

115

550

8 Advances in Materials Science and Engineering

Table 7 Surface tension of the bitumen samples

Bitumen samples Original PFM content wt06 08 10 12

Average value 120590119897 mNm 3304 3138 3134 3146 3142

with the original bitumen (ie without modifying additives)the binder film is persistent on the area of less than 50 ofstonesrsquo surface corresponding to 2 points Addition of 1 wtofmodifier leads to complete coverage of themineralmaterialsurface corresponding to 5 points

The use of PFM improves the thermal stability of bitumen(Table 6) Thus bitumen with PFM additive amounts of09ndash10 wt has lowΔ119905soft equal to 1

∘Cwhile for the bitumenwith ldquoAmidanrdquo Δ119905soft equals 6∘C In addition there has beenimprovement in the penetration which indicates the bitumenbinder improved plasticity

The test results indicate the fact that the increase in thecontent of adhesive additives in the range from 0 to 15 wtleads to increase of penetration values (at 25∘C) namely from67 to 78 (01mm) respectively (Table 6)

The results of adhesive additive ldquoAmidanrdquo testing (Table 6)indicate deterioration of the bitumen properties Though theadhesion is equal for both adhesives ldquoAmidanrdquo acts as adiluting agent leading to increase in the penetration valueThe latest would lead to fractionation (ie delamination)of the binder in the process of its application The changesof ldquoAmidanrdquo-modified bitumen softening temperatures afterheating are too high do not meet the standard requirementsand mean low stability of the binder For that reason no fur-ther tests were carried out for bitumen containing ldquoAmidanrdquo

Regarding the brittleness temperature determinedaccording to Fraas (the Fraass Breaking Point) it indicatesthe lower temperature at which the bitumen loses viscoplasticproperties and as a consequence becomes brittle It is knownthat the lower the brittle point the wider the temperaturerange in which the bitumen is in the viscoplastic state andtherefore the better its physical-mechanical characteristicsIn this case the additive doping allows reducing the brittlepoint and consequently providing expansion of ductilitytemperature range Apart from the above-mentionedadvantages it should be noted that the compounds aresuperior to ldquoAmidanrdquo in adhesion at high temperaturesThus the modified bitumen with additives amount of09ndash10 wt shows high adhesion to sand (5 points) afterthermal exposure at temperatures of 220ndash240∘C for 12 hoursIt should be noted that the bitumen with the same amountsldquoAmidanrdquo exhibits much lower thermal stability providingsimilar adhesion only at temperatures above 170∘C

32 Contact Angle Measurements and Adhesion Work Calcu-lation Figure 5 shows the dependence of the glass surfacewetting contact angle on the content of the additive It isestablished that bitumen does not wet the glass becausecos 120579 has negative values Doping the proposed additive into

bitumen results in a slight increase in wetting ability anextremum is observed with an additive content of 08

Figure 6 shows the dependence of the aggregates wettingcontact angle on the content of the additive It can be seen thatthe presence of an additive significantly changes the wettingof the mineral substrate by the modified bitumen a wettinginversion is observed that is cos 120579 increases with increasingcontent of the additive and acquires positive values We notethat in the case of the surface of mineral materials anextremum is also observed with an additive content of 08by weight

Surface tension measurements results are presented inTable 7

The data in Table 7 indicates that the surface tensiondecreases with the addition of the additive This agrees withthe data of [30] that the surface tension at the bitumen-solidinterface decreases with increasing of surfactants contentSurface tension in combinationwith adhesion properties pro-vides information of the strength of the bitumen adherence tomineral material

The calculated values of the above-mentioned charac-teristics of the ldquoaggregates-organic binderrdquo system surfaceproperties that is wetting energy adhesion work cohesionwork spreading coefficient and relative adhesion work arepresented in Table 8

The analysis of the obtained data shows that the PFMbeing adsorbed at the interface promotes better wetting ofthe aggregates surface with bitumen In this case the contactangle 120579 decreases the spreading coefficient and relativeadhesion work increase reaching a peak when an additivecontent is 08 wt and cohesion work is reduced

The value of119885119886 approaches 1 Consequently the adhesionforces between bitumen and mineral materials approximatein magnitude to the binding forces of the bitumenmoleculesThis contributes to the formation of a material with ahomogeneous defect-free structure

33 Component Composition and Dispersity of the BitumenInformation on the component composition can play animportant role in studying the changes occurring as a resultof bitumen modification (Table 9) Thus when introducingthe developed additive into the initial bitumen in an amountof about 1 by weight mainly the content of saturates inthe direction of decrease and asphaltenes in the direction ofincrease is changing In this case the relative and absolutechanges of the remaining groups of components are insignif-icant

The sequence of hydrocarbon group transitions in thiscase can be delineated as follows [31]

Aromatics (PCA) 997888rarr aromatics (MCA)larr997888 saturates 997888rarr asphaltenes (8)

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

Advances in Materials Science and Engineering 7

Table6Re

sults

oftheq

ualitytests

ofbitumen

mod

ified

with

theu

seof

synthesiz

edcompo

unds

Com

poun

dDosage

Softe

ning

temperature

∘b

Penetration

01m

mDuctilitycm

Adhesio

npo

ints

Brittlenesstemperature

byFraas∘b

Thec

hangeo

fbitu

men

softe

ning

pointafte

rheatin

g(Δ119905 soft)∘b

25∘b

0∘b

25∘b

0∘b

Orig

inalbitumen

mdash497

6722

8455

2minus23

50

Com

poun

d(IIIa

)(119899=1)

01

495

6722

8455

3minus23

mdash025

493

7023

8455

4minus24

30

05

4972

2484

55

5minus26

21

10488

7525

8556

5minus27

1015

485

7826

8657

5minus27

mdash

Com

poun

d(III3)

(119899=2)

01

495

6722

8455

3minus23

mdash025

493

6722

8455

4minus24

32

05

4968

2384

55

5minus26

20

10488

6923

8556

5minus27

1015

485

7024

8657

5minus27

mdash

Com

poun

d(IIIk)

(119899=3)

01

496

6722

8455

3minus23

mdash025

495

6722

8455

4minus24

35

05

493

6823

8455

5minus26

23

10490

6923

8556

5minus27

1015

486

7024

8657

5minus27

mdash

ldquoAmidanrdquo

01

45120

3mdash

025

45120

470

05

45120

565

1046

115

560

1546

115

550

8 Advances in Materials Science and Engineering

Table 7 Surface tension of the bitumen samples

Bitumen samples Original PFM content wt06 08 10 12

Average value 120590119897 mNm 3304 3138 3134 3146 3142

with the original bitumen (ie without modifying additives)the binder film is persistent on the area of less than 50 ofstonesrsquo surface corresponding to 2 points Addition of 1 wtofmodifier leads to complete coverage of themineralmaterialsurface corresponding to 5 points

The use of PFM improves the thermal stability of bitumen(Table 6) Thus bitumen with PFM additive amounts of09ndash10 wt has lowΔ119905soft equal to 1

∘Cwhile for the bitumenwith ldquoAmidanrdquo Δ119905soft equals 6∘C In addition there has beenimprovement in the penetration which indicates the bitumenbinder improved plasticity

The test results indicate the fact that the increase in thecontent of adhesive additives in the range from 0 to 15 wtleads to increase of penetration values (at 25∘C) namely from67 to 78 (01mm) respectively (Table 6)

The results of adhesive additive ldquoAmidanrdquo testing (Table 6)indicate deterioration of the bitumen properties Though theadhesion is equal for both adhesives ldquoAmidanrdquo acts as adiluting agent leading to increase in the penetration valueThe latest would lead to fractionation (ie delamination)of the binder in the process of its application The changesof ldquoAmidanrdquo-modified bitumen softening temperatures afterheating are too high do not meet the standard requirementsand mean low stability of the binder For that reason no fur-ther tests were carried out for bitumen containing ldquoAmidanrdquo

Regarding the brittleness temperature determinedaccording to Fraas (the Fraass Breaking Point) it indicatesthe lower temperature at which the bitumen loses viscoplasticproperties and as a consequence becomes brittle It is knownthat the lower the brittle point the wider the temperaturerange in which the bitumen is in the viscoplastic state andtherefore the better its physical-mechanical characteristicsIn this case the additive doping allows reducing the brittlepoint and consequently providing expansion of ductilitytemperature range Apart from the above-mentionedadvantages it should be noted that the compounds aresuperior to ldquoAmidanrdquo in adhesion at high temperaturesThus the modified bitumen with additives amount of09ndash10 wt shows high adhesion to sand (5 points) afterthermal exposure at temperatures of 220ndash240∘C for 12 hoursIt should be noted that the bitumen with the same amountsldquoAmidanrdquo exhibits much lower thermal stability providingsimilar adhesion only at temperatures above 170∘C

32 Contact Angle Measurements and Adhesion Work Calcu-lation Figure 5 shows the dependence of the glass surfacewetting contact angle on the content of the additive It isestablished that bitumen does not wet the glass becausecos 120579 has negative values Doping the proposed additive into

bitumen results in a slight increase in wetting ability anextremum is observed with an additive content of 08

Figure 6 shows the dependence of the aggregates wettingcontact angle on the content of the additive It can be seen thatthe presence of an additive significantly changes the wettingof the mineral substrate by the modified bitumen a wettinginversion is observed that is cos 120579 increases with increasingcontent of the additive and acquires positive values We notethat in the case of the surface of mineral materials anextremum is also observed with an additive content of 08by weight

Surface tension measurements results are presented inTable 7

The data in Table 7 indicates that the surface tensiondecreases with the addition of the additive This agrees withthe data of [30] that the surface tension at the bitumen-solidinterface decreases with increasing of surfactants contentSurface tension in combinationwith adhesion properties pro-vides information of the strength of the bitumen adherence tomineral material

The calculated values of the above-mentioned charac-teristics of the ldquoaggregates-organic binderrdquo system surfaceproperties that is wetting energy adhesion work cohesionwork spreading coefficient and relative adhesion work arepresented in Table 8

The analysis of the obtained data shows that the PFMbeing adsorbed at the interface promotes better wetting ofthe aggregates surface with bitumen In this case the contactangle 120579 decreases the spreading coefficient and relativeadhesion work increase reaching a peak when an additivecontent is 08 wt and cohesion work is reduced

The value of119885119886 approaches 1 Consequently the adhesionforces between bitumen and mineral materials approximatein magnitude to the binding forces of the bitumenmoleculesThis contributes to the formation of a material with ahomogeneous defect-free structure

33 Component Composition and Dispersity of the BitumenInformation on the component composition can play animportant role in studying the changes occurring as a resultof bitumen modification (Table 9) Thus when introducingthe developed additive into the initial bitumen in an amountof about 1 by weight mainly the content of saturates inthe direction of decrease and asphaltenes in the direction ofincrease is changing In this case the relative and absolutechanges of the remaining groups of components are insignif-icant

The sequence of hydrocarbon group transitions in thiscase can be delineated as follows [31]

Aromatics (PCA) 997888rarr aromatics (MCA)larr997888 saturates 997888rarr asphaltenes (8)

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

8 Advances in Materials Science and Engineering

Table 7 Surface tension of the bitumen samples

Bitumen samples Original PFM content wt06 08 10 12

Average value 120590119897 mNm 3304 3138 3134 3146 3142

with the original bitumen (ie without modifying additives)the binder film is persistent on the area of less than 50 ofstonesrsquo surface corresponding to 2 points Addition of 1 wtofmodifier leads to complete coverage of themineralmaterialsurface corresponding to 5 points

The use of PFM improves the thermal stability of bitumen(Table 6) Thus bitumen with PFM additive amounts of09ndash10 wt has lowΔ119905soft equal to 1

∘Cwhile for the bitumenwith ldquoAmidanrdquo Δ119905soft equals 6∘C In addition there has beenimprovement in the penetration which indicates the bitumenbinder improved plasticity

The test results indicate the fact that the increase in thecontent of adhesive additives in the range from 0 to 15 wtleads to increase of penetration values (at 25∘C) namely from67 to 78 (01mm) respectively (Table 6)

The results of adhesive additive ldquoAmidanrdquo testing (Table 6)indicate deterioration of the bitumen properties Though theadhesion is equal for both adhesives ldquoAmidanrdquo acts as adiluting agent leading to increase in the penetration valueThe latest would lead to fractionation (ie delamination)of the binder in the process of its application The changesof ldquoAmidanrdquo-modified bitumen softening temperatures afterheating are too high do not meet the standard requirementsand mean low stability of the binder For that reason no fur-ther tests were carried out for bitumen containing ldquoAmidanrdquo

Regarding the brittleness temperature determinedaccording to Fraas (the Fraass Breaking Point) it indicatesthe lower temperature at which the bitumen loses viscoplasticproperties and as a consequence becomes brittle It is knownthat the lower the brittle point the wider the temperaturerange in which the bitumen is in the viscoplastic state andtherefore the better its physical-mechanical characteristicsIn this case the additive doping allows reducing the brittlepoint and consequently providing expansion of ductilitytemperature range Apart from the above-mentionedadvantages it should be noted that the compounds aresuperior to ldquoAmidanrdquo in adhesion at high temperaturesThus the modified bitumen with additives amount of09ndash10 wt shows high adhesion to sand (5 points) afterthermal exposure at temperatures of 220ndash240∘C for 12 hoursIt should be noted that the bitumen with the same amountsldquoAmidanrdquo exhibits much lower thermal stability providingsimilar adhesion only at temperatures above 170∘C

32 Contact Angle Measurements and Adhesion Work Calcu-lation Figure 5 shows the dependence of the glass surfacewetting contact angle on the content of the additive It isestablished that bitumen does not wet the glass becausecos 120579 has negative values Doping the proposed additive into

bitumen results in a slight increase in wetting ability anextremum is observed with an additive content of 08

Figure 6 shows the dependence of the aggregates wettingcontact angle on the content of the additive It can be seen thatthe presence of an additive significantly changes the wettingof the mineral substrate by the modified bitumen a wettinginversion is observed that is cos 120579 increases with increasingcontent of the additive and acquires positive values We notethat in the case of the surface of mineral materials anextremum is also observed with an additive content of 08by weight

Surface tension measurements results are presented inTable 7

The data in Table 7 indicates that the surface tensiondecreases with the addition of the additive This agrees withthe data of [30] that the surface tension at the bitumen-solidinterface decreases with increasing of surfactants contentSurface tension in combinationwith adhesion properties pro-vides information of the strength of the bitumen adherence tomineral material

The calculated values of the above-mentioned charac-teristics of the ldquoaggregates-organic binderrdquo system surfaceproperties that is wetting energy adhesion work cohesionwork spreading coefficient and relative adhesion work arepresented in Table 8

The analysis of the obtained data shows that the PFMbeing adsorbed at the interface promotes better wetting ofthe aggregates surface with bitumen In this case the contactangle 120579 decreases the spreading coefficient and relativeadhesion work increase reaching a peak when an additivecontent is 08 wt and cohesion work is reduced

The value of119885119886 approaches 1 Consequently the adhesionforces between bitumen and mineral materials approximatein magnitude to the binding forces of the bitumenmoleculesThis contributes to the formation of a material with ahomogeneous defect-free structure

33 Component Composition and Dispersity of the BitumenInformation on the component composition can play animportant role in studying the changes occurring as a resultof bitumen modification (Table 9) Thus when introducingthe developed additive into the initial bitumen in an amountof about 1 by weight mainly the content of saturates inthe direction of decrease and asphaltenes in the direction ofincrease is changing In this case the relative and absolutechanges of the remaining groups of components are insignif-icant

The sequence of hydrocarbon group transitions in thiscase can be delineated as follows [31]

Aromatics (PCA) 997888rarr aromatics (MCA)larr997888 saturates 997888rarr asphaltenes (8)

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

Advances in Materials Science and Engineering 9

Table8Ph

ysical-chemicalcharacteris

ticso

fthe

ldquoaggregates-organicb

inderrdquosyste

msurfa

ceprop

ertie

s

Bitumen

samples

Diorite

Carbo

nate

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

Wettin

genergy

119882119890m

Nm

Adhesio

nwork

119882119886m

Nm

Coh

esionwork

119882119896m

Nm

Spreading

coeffi

cient119878

Relativ

eadh

esion

work119885119886

0lowast

minus397

2908

6608

minus3701

044

minus330

2974

6608

minus3634

045

06

188

3326

6276

minus2950

053

314

3452

6276

minus2824

055

08

689

3823

6268

minus2445

061

533

3667

6268

minus2601

059

10535

3681

6292

minus2611

059

283

3429

6292

minus2863

055

12409

3550

6284

minus2734

057

251

3393

6284

minus2891

054

lowastAd

ditiv

econ

tentw

t

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

10 Advances in Materials Science and Engineering

minus0483

minus0382

minus0338

minus0388

minus0354

minus050minus048minus046minus044minus042minus040minus038minus036minus034minus032minus030

0 02 04 06 08 1 12Additive content (wt)

cos

Figure 5 Dependence of the glass surface wetting contact angle on the content of the PFM

minus012

006

022017

013

minus01

01 017 009

008

minus015minus01

minus0050

00501

01502

025

0 02

DioriteCarbonate

04 06 08 1 12Additive content (wt)

cos

Figure 6 Dependence of the substrates surface wetting contact angle on the content of the PFM

where PCA is polycyclic aromatics and MCA is monocyclicaromatics

One of the most important characteristics of oil dispersesystem (ODS) is stability since it affects the ability of thesystem to resist internal processes of interaction of particleswith each other which can lead to changes in the particlesize of the dispersed phase and maintain an equilibriumdistribution of dispersed phase particles in the medium[32] Therefore the radius of the particles of the dispersedphase can reach only certain limiting sizes because theprocess of stratification can begin because of the differencein the densities of the phase and the medium The sizes ofdispersed particles can change under the influence of externalfactors (like temperature fluctuations the action of sheardeformations of the medium the action of various additivesetc) [32] In this connection it was necessary to examine thechange in sizes of dispersed particles of bitumen affected byPFM doping The results obtained are presented in Figure 7

As can be seen from the results of measurements inthe medium of toluene-heptane mixture regardless of theratio of solvents the smallest particle diameter correspondsto the additive in bitumen composition equal to 08 by

weight This is due to the fact that the additive provides thedestruction of aggregate combinations with the formationof smaller structures together with their solvation This mayindicate that the bitumen systemwith this PFM content is in astate that can be conditionally called an ldquoactive staterdquo (the coreis minimal and the thickness of the solvate shell is maximal)[32] Apparently with a further increase in the dosage of theadditive a phase inversion that is enlargement of particlestakes place

Thus the PFM doping into bitumen and its heating at120ndash130∘C alters the behavior of some hydrocarbon groups incomparison with the behavior of these groups in the absenceof an additive Based on the results of the group chemicalcomposition it can be concluded that the additive is dis-tributed mainly between monocyclic aromatic hydrocarbonsand asphaltenes As a result of the study of the particle sizeit has been established that the system is in the most ldquoactivestaterdquo with an additive content of PFM in an amount of 08by weight

34 Rheological Properties of Modified Bitumen The rheo-logical properties of the ODS essentially depend on theircomposition and primarily on the content of the main

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

Advances in Materials Science and Engineering 11

Table 9 Group chemical composition of the original and modified bitumen

Componentswt

Bitumen samples

Original PFM content wt06 08 10 12

Saturates (S) 2262 1845 1863 1418 142Aromatics (MCA)lowast 688 874 977 1265 1207Aromatics (BCA + PCA)lowast 826 798 766 685 792Aromatics (A) 1514 1672 1743 195 1999Resins (R) 4026 3947 3907 4065 3992Asphaltenes (A) 2198 2536 2487 2567 2589lowastMCA monocyclic aromatics BCA + PCA bicyclic and polycyclic aromatics

9373 7134 6357 6946 8173

32725 29687

21751

27305

30692

500750

10001250150017502000225025002750300032503500

0 02 04 06 08 1 12

Aver

age p

artic

le d

iam

eter

(nm

)

Additive content (wt)

1 11 2

Figure 7 Dependence of the average diameter of dispersed particlesfrom the content of the additive in toluene heptane medium

structure-forming components which include the mosthigh-molecular components resinous-asphaltene substances(RASs) as well as paraffins at temperatures below theircrystallization temperature which can significantly influenceon the properties of bitumen [31ndash33]

Viscosity increases in proportion to the volume of parti-cles of the dispersed phase and the degree of their aggregation[31ndash33] Aggregation of particles leads to an increase inapparent viscosity since aggregates reduce the effective cross-section of the flow channel and create additional inhibition ofthe displacement of the fluid layers [33] Destruction of thestructure or deformation of solvate shells causes an anomalyof viscosity

Effective regulators of viscosity and the ultimate shearstress of asphaltene-containingODS are surfactants that exertpeptizing action blocking the adhesion planes of particlesand decreasing the strength of contact between the layers ofthe dispersion medium through which the particles of thedisperse phase contact [33]

The viscosity of bitumen depends not only on the com-position of bitumen and its temperature but also on theduration and nature of the action of the load The graph ofviscosity change with temperature is shown in Figure 8 Ascan be seen when all the samples are cooled the viscosityincreases equally but in the initial bitumen the fracture that

000E + 00

500E + 03

100E + 04

150E + 04

200E + 04

250E + 04

300E + 04

80 90 100

0060

100120

080

110 120 130

Figure 8 Dependence of viscosity on temperature

is destruction of the structure begins at a higher temperature(85∘C) than in the modified ones This temperature corre-sponds to the highest viscosity of the original unmodifiedbitumen and is equal to 258 sdot 104 mPasdots

Figure 9 shows the thixotropy curves of bitumen samplesat different temperatures in semilogarithmic coordinates Itshould be noted that at temperatures of 80ndash90∘C viscosityincrease is observed in samples of modified bitumen Theadditive can promote formation of spatial structures due tothe formation of complex structural unit (CSU) conjugatedwith the available particles of the dispersed phase [32] In thiscase the properties of the binder will be determined by thisnew spatial conjugate structure [32]

We assume that the additive provides destruction due topeptization of aggregate combinations of asphaltenes withthe formation of highly disperse RASs that is asphaltenesdisperse into smaller structuresThis conforms to data on theaverage particle diameter (Section 33) in which the smallestparticle diameter corresponds to the dosage of the additive inthe bitumen of 08 wt As a result the amount of particlesincreases and thereby the viscosity increases due to the largercontact surface Summarizing the foregoing we should notethat the additive has a structuring effect on the properties ofroad bitumen that is expressed in the formation of a spatialdispersed structure conjugated with asphaltene complexesof bitumen [31] The structuring effect is manifested with acertain concentration and only in the presence of a spatial

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

12 Advances in Materials Science and Engineering

012345

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0 100120080

(a)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(b)

0123456

0 100 200 300 400 500 600 700 800 900 1000Shear rate (Ｍminus1)

lg

0060

100120

080(c)

Figure 9 Curves of thixotropy of samples at temperatures ∘b (a) 80 (b) 85 (c) 90

Table 10 Results of laboratory tests of oxidized bitumen 6090

Number Indicators GOST 22245-90requirements

Bitumen samples

Original Adhezoline content wt06 08 10 12

(1) Penetration 01mm Not belowat 25∘b 61ndash90 73 75 81 86 78at 0∘b 20 25 30 30 25 23

(2) Softening temperature (119879soft)∘b Not below 47 514 498 496 50 49

(3) Ductility cm Not less thanat 25∘b 55 89 128 116 110 120at 0∘b 35 45 49 50 45 49

(4) Adhesion to crushed stone points(1) Pervouralsk

Is not regulated

2 4 4 5 5(2) Sangalyk 2 4 4 5 5(3) Bianca 3 5 5 5 5(4) Valegin Bor 2 4 5 5 5

(5) Penetration index From minus1 to +1 01 minus02 minus01 02 minus03

(6) Brittleness temperature ∘b Not higher than minus15

Minus229

Minus237

Minus257

Minus291

Minus288

coagulation structure in the bitumen [31] It is likely that thisspecific concentration in the bitumen is 08 wt which wecalled the ldquoactive staterdquo (Section 33)

35 The Effect of PFM on Bitumen Performance PropertiesThe results of laboratory tests carried out on bitumenmodified using 06 08 10 and 12 wt of additive arepresented in Table 10 in comparison with the GOST 22245-90 requirements

The interrelation between the changes in the quality indi-cators of bitumen given in Table 10 can be explained on thebasis of the specificity of the action of the synthesized reagentand its subsequent polymerization activity when the groupcomponent composition and the particle size of the dispersedphase change Thus according to 119879soft value changes theconcentration of PFM of 06 wt is characterized by anincrease in the structure formation (119879soft = 128∘b) and anincrease in the mechanical strength of the ODS with an

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

Advances in Materials Science and Engineering 13

increase in the concentration of PFM up to to 08ndash10 wtwe observe a sharp drop in the value of softening point to116∘b and 110∘b respectively Apparently this indicates thedisaggregation of resinous-asphaltene particles (RAS) in thedispersion medium of the modified bitumen by the PFM

The indicator ldquopenetration indexrdquo (PI) is considered asa reflection of the colloidal structure of bitumen Takinginto account the fact that with the change of penetrationof bitumen the ductility indicator passes through the maxi-mum value the penetration index is limited from minus1 to +1It is known that the PI indicator accurately characterizesthe elastic properties of bitumen and their dependence ontemperature [15 31] For the studied samples the PI indicatorchanges from +01 (for the original unmodified bitumen) tothe values of minus02 minus01 +02 for the concentrations (wt)of PFM equal to 06 08 10 respectively Thus the increasein the content of PFM up to 10 wt increases the elasticityof modified bitumen At the same time an important trend isobserved the further increase in the concentration of additiveup to 12 wt leads to a sharp decrease in PI to minus03 whichis directly proportional to the penetration indicator Thisindicates the activation of the structure formation of thedisperse system of modified bitumen

The use of bitumen as film-forming base in asphaltmaterials is justified primarily by the fact that the rate ofdiffusion of water into the bitumen is 083 sdot 10minus15ndash166 sdot10minus15 kgsdotm(ssdotN) [5] this causes low solubility of water inthe bitumen As mentioned above the degree of adhesionbetween the bitumen and the stone material depends on thechemical nature of the components and therefore the varietyof types of bitumen and the stone material [4 16]

The process of adhesive bond forming is usually dividedinto two stages The first is the so-called transport stageduring which adhesive molecules move to the surface of thesubstrate (body on which the adhesive is applied) and thefunctional groups of the adhesive interact orientating in theinterphase layerThis results in intimate contact of moleculesandor associates of the adhesive with the substrate Anincrease in temperature and pressure as well as conversion ofone of the phases (typically an adhesive) to the liquid state bydissolving or melting contributes to the flow of the first stageof the adhesion process To achieve a more intimate contactbetween the adhesive and the substrate we can apply morethorough cleaning of the interacting surfaces The adhesionsecond step consists in direct intermolecular interaction ofthe adhesive and substrate which may be caused by thedifferent forces from van der Waals to chemical forcesIntermolecular interactions of contacting phases completethe adhesion process and that corresponds to the minimumof interfacial (surface) energy [16]

We have developed a polyfunctional modifier of complexaction that is a nonclassical cationic surfactant as mentionedabove Based on the foregoing conceptualization it is possibleto assume that the efficiency of PFM is due to the presenceof discontinuities in hydrophobic hydrocarbon chains causedby presence of polar heteroatomic moieties which providethe required hydrophilic-lipophilic balance (HLB) as well as

1

2

3

4

5

163 180 200 163 180 200

5 hours10 hours15 hours

20 hours25 hours

Adhe

sion

poi

nts

Basic rocks Acidic rocks

Temperature (∘C)

Figure 10 Thermal stability of bitumen modified with the use ofPFM

the optimal location of these polar groups and hydrophobichydrocarbon radicals in the adhesive molecule In additionin this case the length of the nonpolar hydrocarbon chainsand their location has a great influence All this allows us toprovide themost effective interaction of PFMwith the surfaceof the dispersed phase and the volume of the dispersionmedium

According to the existing technology of preparation ofasphalt mixtures used in the asphalt plants asphalt under-goes high temperatures The essential drawback of adhesiveadditives currently used in road construction is their thermalinstability (up to 140ndash150∘C)

The results of research for the thermal stability of bitumenmodified by PFM (as determined above the optimal amountof 08 wt was doped) are presented in Figure 10

As can be seen from the data presented in Figure 10the temperature control at 163∘C for 20 hours provides theadhesion degree evaluated with 5 points which correspondsto the control sample No (1) Increasing the heating durationat the same temperature for up to 25 hours leads to somereduction in adhesion An influence of temperature of 180∘Cand 200∘C for 10 hours and more leads to a decrease inadhesion down to 4 points It should be noted that thebitumen without additive has shown insufficient adhesionboth with basic and acidic rocks namely 3 points afterthermal exposure for 5 and 10 hours and 2 points after 15ndash25hours thermal exposure (at all the temperatures)

Thus the synthesized polyfunctional modifier signifi-cantly improves the adhesion of the bitumen to the surface ofthe mineral material and pavements with enhanced thermalstability

We had conducted pilot-scale tests with the road con-structing organization ZAO Trest Kamdorstroy The resultsof technical inspection have shown that asphalt concretemixtures obtained with the use of modified bitumenmeet theGOST 22245-90 specification quality requirements

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

14 Advances in Materials Science and Engineering

Field tests carried out to assess the physical and mechan-ical characteristics of asphalt concrete mixtures based onbitumen BND 6090 produced by JSC ldquoTAIF-NKrdquo modifiedusing 1 wt of PFM taken from the coating after two yearsand 9 months of operation of the roadway have shownthat these asphalt mixes fully comply with GOST 9128-2009 ldquoMixtures of asphalt concrete road airfield and asphaltconcreterdquo

Thus the results obtained give grounds to judge theincrease in the between-repair time of the road surface andas a consequence its durability as a result of the use of PFM-modified bitumen

4 Conclusion

The experimental data indicate a high capacity of N-acylatedderivatives of bisimidazolines to improve the adhesion ofbitumen to mineral materials as well as the plasticity of bitu-men while providing increased (up to 220ndash240∘C) thermalstabilityThe polyfunctional modifier can be used as complexadditives for bitumen used in road and civil constructionregardless of the nature of used aggregates (basic or acidic)and regardless of the change in composition of the originalbitumen

Thus it was found that the presence of an adhesiveadditive in the bitumen significantly changes the wetting ofthe mineral substrate with modified bitumen The wettinginversion is observed cos 120579 increases with increasing contentof the additive it acquires positive values the work ofadhesion increases reaching a peak with an additive contentof 08 by weight the work of cohesion and the surfacetension between the liquid and solid phases decrease

It has been established that the smallest particle diametercorresponds to the dosage of the additive in the bitumen of08 by weight so that it can be concluded that the additivehas a structuring effect on the properties of road bitumen

The use of PFM leads to improved performance proper-ties enabled by lowering the binder sensitivity to temperaturechanges and load time susceptibility as well as providinghigh adhesion between the binder and aggregates at elevatedtemperatures in combination with high elasticity at lowtemperatures

Finally it should be noted that from January 2015 toJanuary 2016 the experiments were conducted to evaluatethe adhesive properties of bitumen in various weather condi-tions So on January 14 2015 a previously prepared sample ofbitumenmodified by PFM in the amount of 1 wtwas placedoutside and kept under different weather conditions for oneyear after which the sample of the bitumen was monthlyexamined for its adhesion properties Over a year outsidetemperatures changed from minus 25∘C in winter to plus35∘C in the summer The obtained data on the evaluationof adhesion proved to be quite satisfactory Bitumen hasnot lost its adhesive properties during the whole period ofstorage in the open air at various temperatures which canalso indirectly confirm the increased durability of this kindof bitumen and asphalt concrete on its basis

Conflicts of Interest

The authors declare that they have no conflicts of interest

Acknowledgments

Thework is performed according to the Russian GovernmentProgram of Competitive Growth of Kazan Federal UniversityThis work was funded by the subsidy allocated to KazanFederal University for the state assignment in the sphere ofscientific activities (107636201778)

References

[1] R Hunter The Shell Bitumen Handbook ICE PublishingLondon UK 6th edition 2014

[2] L M Gokhman ldquoBitumens bitumen-polymer binders asphaltconcrete polymeric asphalt concrete study guiderdquo (Russian) p117 ZAO ldquoECON-INFORMrdquo 2008

[3] S Manolis ldquoEngineering properties of asphalt cement bindersand their relation to pavement performancerdquo Royal MilitaryCollege of Canada Coco Paving Inc 2014 httpwwwasphalt-instituteorgwp-contentuploadsThickness Mix2014-pptbyManolis-EngineeringPropertiesofACBindersandRelationtoPavement-Performancepdf

[4] A F Burger M F C van de Ven J Muller and K J JenkinsldquoRheology of polymer modified bitumen A comparative studyof three binders and three Binderfiller systemsrdquo in Proceedingsof the 20th South African Transportation Conference ldquoMeetingthe Transport Challenges in Southern Africardquo 2001

[5] A F Kemalov and R A Kemalov ldquoStudy of disperse poly-mer systems for producing high-quality polymeric-bituminousmaterialsrdquo Chemistry and Technology of Fuels and Oils vol 48no 5 pp 339ndash343 2012

[6] X Lu Y Talon and P Redelius ldquoAging of bituminous bindersndash laboratory tests and field datardquo in Proceedings of the EampECongress Copenhagen Denmark 2008

[7] S Cui B R K Blackman A J Kinloch and A C TaylorldquoDurability of asphalt mixtures Effect of aggregate type andadhesion promotersrdquo International Journal of Adhesion andAdhesives vol 54 pp 100ndash111 2014

[8] A Chomicz-Kowalska W Gardziejczyk and M M IwanskildquoMoisture resistance and compactibility of asphalt concreteproduced in half-warm mix asphalt technology with foamedbitumenrdquoConstruction andBuildingMaterials vol 126 pp 108ndash118 2016

[9] A A Abramzon V V Bocharov G M Gayevoy et alSurfactants Khimiya Leningrad Russia 1979 (Russian)

[10] D N Rubingh and P M Holland Cationic Surfactants PhysicalChemistry vol 37 of Surfactant Science Marcel Dekker IncNew York NY USA 1990

[11] J-Z Ai X-P Guo J-E Qu and Z-Y Chen ldquoAdsorptionbehavior of imidazoline amide on the surface of galvanicelectroderdquo Acta Physico - Chimica Sinica vol 21 no 10 pp1096ndash1101 2005

[12] V V Krutrsquo A B Solomentsev V P Kolodezny et al ldquoAdhezionadditive of polyfunctional actionrdquo pat 2130954 Russian Federa-tion IPC C08L9500 C08K53415 applicant and patent holderOAO Oreldorstroy - No 9710088404

Advances in Materials Science and Engineering 15

[13] A F Kemalov R A Kemalov and I M Abdrafikova ldquoThe useof plant oils for gaining the colored plastoconcreterdquo BiosciencesBiotechnology Research Asia vol 11 no 3 pp 1699ndash1706 2014

[14] S Kishchynskyi V Nagaychuk and A Bezuglyi ldquoImprovingQuality and Durability of Bitumen and Asphalt Concreteby Modification Using Recycled Polyethylene Based PolymerCompositionrdquo Procedia Engineering vol 143 pp 119ndash127 2016

[15] I I Mukhamatdinov Bitumen binders modified with the use ofcationic-active adhesion additive [PhD Thesis] Kazan FederalUniversity 2015

[16] NPCS Board of Consultants amp Engineers The Complete Tech-nology Book on Industrial Adhesives Asia Pacific Business PressInc Delhi India 2008

[17] P S Fakhretdinov ldquoThe concept of non-classic cationic sur-factantsrdquo in Proceedings of the XVIII Mendeleev Congress onGeneral and Applied Chemistry vol 1 p 483 Moscow Russia2007

[18] P S Fakhretdinov and G V Romanov ldquoThe concept of non-classic surfactants is the basis for the creation of new highlyeffective reagents for the petroleum industryrdquo in Proceedingsof the the 2nd Russian Scientific-Practical Conference ldquoPracticalAspects of oilfield chemicalsrdquo p 104 Ufa Russia 2012

[19] A F Kemalov and R A Kemalov ldquoPractical Aspects ofDevelopment of Universal Emulsifiers for Aqueous BituminousEmulsionsrdquo World Applied Sciences Journal vol 23 no 6 pp858ndash862 2013

[20] A P Kreshkov L N Bykova and N A Kazaryan AcidndashBaseTitrations in Non-Aqueous Solutions Khimya Moscow Russia1967

[21] B N Tarasevich IR Spectra of the Main Classes of OrganicCompounds Reference Materials MV Lomonosov MoscowState University Moscow Russia 2012

[22] GOST 12801-98 ldquoMaterials based on organic binders for roadand airfield construction Test methodsrdquo 1999

[23] A W Neumann and R J Good ldquoTechniques of measuringcontact anglesrdquo in Surface and Colloid Science R J Good andR R Stromberg Eds vol 11 pp 31ndash91 Springer New York NYUSA 1979

[24] GOST 22245-90 ldquoViscous petroleum road bitumens Specifica-tionsrdquo 1991

[25] GOST 18180-72 ldquoPetroleum bitumens Method for determina-tion of mass change after heatingrdquo 1973

[26] GOST 3900-85 ldquoPetroleum and petroleum products Methodsfor determination of densityrdquo 1987

[27] GOST 33-2000 ldquoPetroleum products Transparent and opaqueliquids Determination of kinematic viscosity and calculation ofdynamic viscosityrdquo 2002

[28] ASTM D 2872 ldquoStandard test method for effect of heat and airon moving film of asphalt (Rolling thin-film oven test)rdquo TechRep

[29] GOST 9128-2009 ldquoAsphalt concrete mixtures for roads andairdromes and asphalt concrete Technical specificationsrdquo 2011

[30] R B Gun Petroleum Bitumen Chemistry Moscow Russia1973

[31] S M Petrov Modifiers of multifunctional action for obtainingoxidized road bitumen with improved properties [PhD Thesis]Kazan State Technological University Kazan Russia 2009

[32] B P Tumanyan Scientific and Applied Aspects of the Theory ofOil Dispersed Systems Tekhnika Moscow Russian 2000

[33] G I Fuchs Viscosity and Plasticity of Petroleum ProductsInstitute for Computer Research Moscow-Izhevsk 2003

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom

CorrosionInternational Journal of

Hindawiwwwhindawicom Volume 2018

Advances in

Materials Science and EngineeringHindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Journal of

Chemistry

Analytical ChemistryInternational Journal of

Hindawiwwwhindawicom Volume 2018

ScienticaHindawiwwwhindawicom Volume 2018

Polymer ScienceInternational Journal of

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

Advances in Condensed Matter Physics

Hindawiwwwhindawicom Volume 2018

International Journal of

BiomaterialsHindawiwwwhindawicom

Journal ofEngineeringVolume 2018

Applied ChemistryJournal of

Hindawiwwwhindawicom Volume 2018

NanotechnologyHindawiwwwhindawicom Volume 2018

Journal of

Hindawiwwwhindawicom Volume 2018

High Energy PhysicsAdvances in

Hindawi Publishing Corporation httpwwwhindawicom Volume 2013Hindawiwwwhindawicom

The Scientific World Journal

Volume 2018

TribologyAdvances in

Hindawiwwwhindawicom Volume 2018

Hindawiwwwhindawicom Volume 2018

ChemistryAdvances in

Hindawiwwwhindawicom Volume 2018

Advances inPhysical Chemistry

Hindawiwwwhindawicom Volume 2018

BioMed Research InternationalMaterials

Journal of

Hindawiwwwhindawicom Volume 2018

Na

nom

ate

ria

ls

Hindawiwwwhindawicom Volume 2018

Journal ofNanomaterials

Submit your manuscripts atwwwhindawicom