Challenges, Opportunities and Solutions in Structural Engineeringand Construction Ghafoori (ed.)

2010 Taylor & Francis Group, London, ISBN 978-0-415-56809-8

Investigations on flexural behavior of high strength manufacturedsand concrete

V. Bhikshma, R. Kishore & C.V. Raghu PathiDepartment of Civil Engineering, University College of Engineering, Osmania University, Hyderabad, India

ABSTRACT: Sand is basic concrete making construction material required in large quantities. Hence, in thepresent scenario, it is necessary to find the most suitable substitute for sand, easy to produce and has all therequired qualities for use in concrete. Manufactured sand is one among such materials to replace river sand,which can be used as an alternative fine aggregate in mortars and concretes. To attain the set out objectives of thepresent investigation, M50 grade concrete has been considered. Strength properties such as cube compressivestrength and flexural strength of beams, and load carrying capacity, moment carrying capacity, behavior of strainsin compression as well as tension fibers and cracking patterns have been studied for the grade of concrete. In thispaper a total of 15 cube specimens 150 150 150 mm and 10 beam specimens of size 1500 150 230 mmwere cast for testing. The results have been compared for the specimens made with natural fine aggregate.

1 INTRODUCTION

Construction has become technology oriented withnew and better materials and techniques being devel-oped. In this quest, better materials and techniques inconstruction have gained a strong foothold and foundwide applications. However, considerable research isstill to be done in the field of building materials toreduce building costs further and improved structuralperformance. Concrete is one of the versatile construc-tion materials widely used by the industry. Continuousresearch efforts have established concrete as a versatilematerial. Conventionally concrete is a mix of cement,fine and coarse aggregates. The use of manufacturedsand in concrete is gainingmomentum these days. Thepresent experimental investigations have been madeon concrete using manufactured sand as fine aggre-gate and observed the effects of crushedmanufacturedsand on strength properties of concrete.

1.1 Aims and objectives

1. To examine theworkability of different percentagesof manufactured sand concrete and compare withnatural sand concrete.

2. To investigate the performance of different percent-ages ofmanufactured sand concrete beams in termsof its load carrying capacity and moment carryingcapacity and compare with corresponding naturalsand concrete beams.

1.2 Scope of present investigation

Conventional concrete and M50 grade of concretefrom 25%, 50%, 75% & 100% of manufactured Sand

have been considered for casting concrete cubes andbeams. Also 30 concrete cubes and 10 reinforcedbeams have been considered forM50grade of concrete

2 LITERATURE REVIEW

Hudson reported that Concrete Manufactured witha high percentage of minus 75 micron material willyield a more cohesive mix than concrete made withtypical natural sand. Water absorption according toMisra V.N., the percentage of water required to pro-duce mortar of same consistency is high for Robosand as compared to river sand of same grading andsame mix proportions. Srinivasa Rao P. has found thatas percentage of stone dust increases the workabilitydecreases in each grade of concrete to compensate thedecrease in workability, some quantity of water andcement were added to get normal workability. Thepercentage of increase in water is in the range of 5%to 7%. Bhanuprabha, observed that the percentage ofweight for M20, M25 and M30 grade manufacturedsand concrete increased in 5% H2S04 and 5% Na2S03acid compared to plain concrete and found to be as30.3%, 24.4%, 22.9%; and 5.3%, 2.2%,1.25% respectively. The negative sign indicates lessreduction in weight loss that means the concrete isslightly more durable to sulphuric acid attack and sul-phate attack when compared to river sand. SrinivasaRao P., and Giridhar V. have observed that the con-crete prepared using crusher stone dust was foundto be relatively less workable than those comparedwith river sand. Hudson B.P. has reported that thereis considerable increase in the compressive strength

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when concrete is made of higher amount of minus 75-micron material. Comparing with natural sand, Srini-vasa Rao.P has observed an increase in compressivestrength by 15% for M20 and M30 grades of con-crete and by 1213% for M40 grade of concrete whenthe concrete is made of stone dust. Giridhar V. hasobserved that, for the concretemadewith crusher dust,there is an increase of 6% strength split tension andan increase of 20% strength in flexural tensile tensionat 28 days for M20 grade design mix. Dinesh Kharehas reported that flexural tensile stress of the concreteincreases as percentage of Robo sand increases.

3 EXPERIMENTAL PROGRAMME

3.1 Materials used

Ordinary Portland cement of 53 grade confirming toBureau of Indian Standard is used in the present study.Steel For longitudinal tensile reinforcement, 12 mmand 10 mm dia tor steel and 6 mm dia mild steelwere used for stirrups. The locally available river sandpassing through IS sieve no: 480 was used as fineaggregate. Manufactured sand (Robo Sand) used forthe present study was procured from M/S Robo Sili-con Pvt. Ltd. from their plant near Hyderabad AndhraPradesh India. Test results are presented in Tables 24.

3.2 Concrete mixing

All thematerials required formaking the concretewereweighed as per the required proportion and kept readyfor use before the mixing started. Cement, Fine aggre-gate and coarse aggregate were mixed thoroughly inthe dry state. The water is added finally to the drymixture. Superplasticiser (SP 337) were mixed in thewater for M50 conventional and M50 grade using dif-ferent proportions of Robo Sand. For M50 grade withvarying percentages of Manufactured sand (0%, 25%,50%, 75% and 100%.) of concrete, the cross sectionsof the beams adopted were 150 mm in width and230mmindepth. The lengthof the beamwas1500mm.The mix proportions adopted are presented in Table 1.

3.3 Compressive strength

Compressive strength of the various strength of con-crete, the determination of compressive strength hasreceived a large amount of attention because the con-crete is primarily meant to withstand compressivestresses. Generally, cubes are used to determine thecompressive strength. In the present study the cubesof 150 mm 150 mm 150 mm size are used.

3.4 Loading arrangements and testing procedure

The beams were mounted on the wing table of 200tons universal testingmachine inNorth-Southdirection.

Table 1. Mix proportions of concrete.

M50

R.S. R.S. R.S. R.S. R.S.Materials 0% 25% 50% 75% 100%

Cement 1 1 1 1 1Sand 0.90 0.675 0.45 0.225 Manufactured

sand 0.225 0.45 0.675 0.90Coarse

aggregate 2.27 2.27 2.27 2.27 2.27Water/Cement

ratio 0.30 0.30 0.30 0.30 0.30Sp (ml) 350 350 350 350 350

Table 2. Physical properties of cement.

Tests conducted Value obtained

Normal consistency 32%Initial setting time 85 minutesFinal setting time 300 minutesSpecific gravity of cement 3.15Compressive strength 7 days

with natural sand 41.2 N/mm2

Compressive strength28 days with natural sand 58.523 N/mm2

Compressive strength 7 dayswith manufactured sand 44 N/mm2

Compressive strength28 days with manufactured sand 61.365 N/mm2

Fineness 2%Bulk density of cement 1.35 gm/cc

Table 3. Properties of steel.

PercentageDiameter Proof stress elongation

Tor steel 12 mm dia 445 460 28Tor steel 10 mm dia 434 458 25Mild steel 6 mm dia 263 275 23

The beams were simply supported on steel rollersof 38 mm in diameter that were kept in speciallyprepared moulds. The specimens were tested undertwo-point transverse loading with simply supportedspan of 1200 mm. An iron roller was kept between thebeam and UTM, at the two points of contact at a dis-tance of 400 mm, so that the load transferred was liketwo point loads. After fixing the deflection and straindial gauges to the beam specimens at the specifiedpoints, uniform load was applied.

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Table 4. Properties of fine and coarse aggregates.

Tests conducted Value obtained

Specific gravity of fine aggregate(Natural river sand) 2.53

Specific gravity of fine aggregate(Manufactured sand) 2.65

Specific gravity of coarse aggregate 2.75Compacted bulk density of

fine aggregate (sand) 17.59 kN/m3

Loose bulk density of fineaggregate (sand) 17.03 kN/m3

Compacted bulk density of fineaggregate (Manufactured Sand) 18.36 kN/m3

Loose bulk density of fineaggregate(Manufactured Sand) 17.03 kN/m3

Compacted bulk density of coarseaggregate 15.40 kN/m3

Loose bulk density ofcoarse aggregate 14.13 kN/m3

Fineness modulus of fine aggregate(sand) 2.68

Fineness modulus of fine aggregate(manufactured sand) 2.701

Fineness modulus of coarse aggregate 6.251

4 TEST RESULTS AND DISCUSSIONS

4.1 Reinforced concrete beams

The experimental investigation has been carried out tostudy the behavior and strength of reinforced concretebeams with manufactured sand and natural sand asfine aggregate. For this purpose two beams each ofconcrete with manufactured sand and natural sand foreach grade of concrete are tested under two point load-ing for pure bending and corresponding test resultshave been shown in Table 3.

4.2 Load vs deflection relation

The performances of reinforced concretemembers canbe reviewed from load vs. deflection curves. All thespecimen curves are presented in Figures 23.

4.3 Compressive strength of concrete usingmanufactured sand as fine aggregate

It is observed from the Table that the seven days and28 days cube compressive strength of concrete madewith manufactured sand improved the cube compres-sive strength by 6.89%, 10.76%, 17.24% and 20.68%for M50 grade varying ratios respectively than theconcrete made with natural sand.

4.4 Strength of manufactured sand concrete beams

Ultimate strength of reinforced concrete beams interms of load carrying capacity and moment carrying

Figure 1. Compressive strength variation with percentagereplacement of Robo Sand for M50 grade concrete.

Figure 2. Relationship between load vs deflection for M50grade concrete.

Figure 3. Relationship between load vs deflection for 100%Robo concrete.

capacity: It is noticed that the ultimate strength ofmanufactured sand concrete beams are slightly higherthan those comparedwith conventional concrete beams,which is around 3 to 12% forM50 grade varying ratiosof concrete respectively.

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Table 5. Workability of concrete.

Workability

Type of fine Compactionaggregate Slump (mm) factor

Robo sand (0%) 55 0.87Robo sand (25%) 48 0.83Robo sand (50%) 44 0.80Robo sand (75%) 41 0.75Robo sand (100%) 38 0.72

Table 6. Designation of beam specimens.

Beam Percentage ofdesignation reinforcement No. of beam specimens

RS(0%) 2.04% 2RS(25%) 2.04% 2RS(50%) 2.04% 2RS(75%) 2.04% 2RS(100%) 2.04% 2

M50 Grade, Letter R: Robo, S: Sand.

Table 7. Details of reinforcement.

Beam designation Reinforcement

RS 0% (M50 grade natural 4 nos 12tor +2 nossand concrete) 10tor Main Reinforcement

and 2L-6 mm mild @150 mm c/c for stirrups

RS 25%, RS 50%, RS 75%, 4 nos 12tor +2 nosRS 100% M50 grade 10tor Main Reinforcementmanufactured sand and 2L-6 150 mm c/cconcrete) for stirrups

Table 8. Compressive strength of concrete.

Compressivestrength (MPa)

M50 7 Days 28 Days

R.S. 0% 40 58R.S. 25% 45 62R.S. 50% 48 65R.S. 75% 49 68R.S. 100% 51 70

4.5 Structural behavior manufactured sandconcrete beams

The load vs. deflection of manufactured sand concretebeams for a particular grade of concrete and percent-age of reinforcement, right up to the failure, have been

Table 9. Test results of ultimate moment, curvature anddeflections.

Ultimate Ultimateload moment Curvature Deflection

Mix pro. (kN) (kNm) 105 (mm)R.S. 0% 64 30.23 4.96R.S. 25% 165 66 11.16 5.6R.S. 50% 170 68 10.12 5.55R.S. 75% 175 70 9.57 6.12R.S. 100% 180 72 8.98 6.12

studied. It was observed that the deflection responsewas slightly less for the same loading conditions whencompared with natural sand concrete beams. All testresults are presented in Tables 59.

5 CONCLUSIONS

Workability of the M50 grade manufactured sandconcrete observed to be 30% less compared to theconventional concrete.

The compressive strength of M50 grade concretewith varying percentages of (0%, 25%, 50%, 75%,and 100%) manufactured concrete improved thestrengths by 6.89%, 10.76%, 17.24%, 20.68%,respectively.

The load carrying capacity and Moment carryingcapacity of the RC beams of manufactured sandconcrete obtained 3 to 12% when compared to con-ventional concrete.

Manufactured sand can be substituted in makingstructural grade concrete, as it is giving satisfactoryperformance.

REFERENCES

Bhanuprabha., Studies on use of manufactured sand as FineAggregate M. Tech dissertation, submitted to JNTU,Hyderabad, 2003, India.

DineshKhare., Marvelous properties of StoneCrusher dust:AWaste bye-product of stone crushers, National confer-ence on Advances of construction material, 2002, Hamir-pur (H.P.), India. Pages 189 to 195.

Giridhar, V., Strength characteristics of concrete usingcrusher stone dust as fine aggregate, 63rd Annual Gen-eral meeting, 23rd December 2000, Hyderabad. Pages 11to 15.

Hudson, B.P., Manufactured sand for concrete, ICJ,August1999.

Misra, V.H., Use of Stone dust from crusher in cement andsand Mortar ICJ, August 1984.

Srinivasa Rao, P., Seshagiri Rao, M.V. and Sravana., Effectof crusher stone dust on some properties of concrete,National conference on advances in construction materi-als, 2002, Hamirpur. (H.P. India pages 196 to 201).

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Challenges, Opportunities and Solutions in Structural Engineeringand Construction Ghafoori (ed.)

2010 Taylor & Francis Group, London, ISBN 978-0-415-56809-8

Moisture permeability and sorption-desorption isotherms of some porousbuilding materials

R. MiniotaiteKaunas University of Technology, Kaunas, Lithuania

ABSTRACT: The durability of surface layers of enclosures (outside walls of buildings) is highly influencedby stresses that occur in the plane of contact between finishing materials and that of the enclosure. Varia-tions of sorption moisture in the surface layer of enclosures result in deformations which have to be evaluatedtogether with sorption-desorption processes in the construction and expressed in specific moisture-caused defor-mation of construction material. The dependence of the basic building materials of enclosure constructionsupon change in material moisture with variation of relative humidity of the air was investigated by way ofexperiments.

1 INTRODUCTION

Adsorption-desorption processes taking place inconstruction materials basically indicate the natureof mechanical, physical and molecular bond betweenmaterial and water or its vapour. In designing and con-struction practice, it is customary to relate adsorption-desorption calculations with the air-dry materials.Usually, the permitted moisture content, estimatedstrength, thermal conductivity, swelling, shrinkageand other physical andmechanical values are indicatedwithin the limits ofmaterial hygroscopicmoisture (ENISO 12571 2000; Cerny et al. 1996; Lentinen 1996).

The following stages of material humidity state arepredetermined by adsorption-desorption processes:

material moisture content when the walls of cap-illaries and pores of the material are covered withwater molecules;

material moisture content when vapour is prevail-ing in pores and capillaries;

material moisture content at the beginning and dur-ing intense development of capillary condensation,i.e. such air conditions are shown when water andnot vapour prevails in the capillaries of the materialmaintained.

According to the physical data on the above stages,one can judge about the ratio of moistening and dry-ing velocities, destruction of the material in the areaof microcapillaries and micro-cracks, softening ofthe material as well as swelling-shrinkage (moisture-caused) deformations and fatigue of the material(Freitas et al. 1996; Carmeliet&Roels 2001; Bomberget al. 2001).

2 INVESTIGATION METHOD

The data on adsorption-desorption processes found inliterature are fragmentary, not exhaustive and char-acterize only the limit or typical values of the abovementioned properties of some traditional materials(Ramos&Freitas 2006; Hedenblad 1993; Carmeliet&Roels 1996).

Standard methodics intended for determination ofadsorption-desorptionwere not exhaustive. Theywereinsufficient for investigation of adsorption-desorptionprocesses and therefore had to be essentially improvedin the course of investigation.

The main point of the developed adsorption-desorption method is carrying out of experimentsin three stages (Miniotaite 1999a, b, 1998, 2004).At the first stage, sorption isotherm of the investiga-tive material is drawn at all 7 points of ambient airhumidity . At the second stage, a reverse action isapplied, i.e. desorption isotherm of the same specimenis drawn. At the third stage, desorption process is atsome moment discontinued; coming back to sorption,physical coordinates of such moment are fixed: rela-tive humidity (RH) of ambient air and specimensmoisture content u.

When adsorption-desorption experiment at 20Ctemperature is completed, the investigated materialsare placed in a vessel and dried again; analogous exper-iment is carried out at 5C.

It was found in literature only approximate data onsorption moisture content of materials in case of tem-peratures below zero, even though surface layers ofwalls are under action of the environment of temper-atures below zero for a long period of time (on the

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average, 100.3 days per year in Lithuania). With thedata on adsorption-desorption processes at 20C and5C, rather precise recalculation of sorption moisturecontent at low temperatures is possible on the basis ofClausius-Clapeyrons equation:

d ln p

dT= L

RT 2(1)

The integral of the above equation within the tem-perature range from T1 to T2 when L = const, permitsto calculate the pressure p1:

ln p1(T1) = ln p2(T2) LR(

1

T1 1

T2

)(2)

where: T = temperature, K; T1 < T2; L is heat ofphases change, J/mol. In general case it consists ofheat of evaporation, ice melting heat and adsorptionheat. Ice melting heat is used only for temperaturesbelow 0C. R is universal gas constant, J/(K mol);p is saturated vapour pressure, Pa; p1 < p2. Sorp-tion moisture content u are calculated of p values andrelative humidity values.

Adsorption-desorption investigations of the mate-rials were carried out at 20C and 5C according tothe improved methods of sorption investigation. Thensorption isotherms were recalculated in isotherms at10C, 0C and 10C.

3 RESULTS AND ANALYSIS

Graphic and summarized passports-cards ofadsorption-desorption investigations of all testedmaterials are made up indicating a structural group ofthe material corresponding to similarity of moisture-caused deformations, the name of material and themain adsorption-desorption parameters. The pass-ports-cards constitute a respective data bank onadsorption-desorption of construction material.

A typical example of such a passport-card is givenin Figure 1. It should be noted that at temperaturesbelow zero significant difference between experimen-tal results and literary data is observed. According toliterary sources, material moisture content u increaseswith drop in temperature whereas according to exper-imental results, at high values of RH of the air andtemperature below 0C, material moisture content uis substantially less than that of isotherms at tempera-tures above 0C.

Generalizing the nature of changes in adsorption-desorption isotherms it was determined that no dis-tinct limits exist between individual forms of materialhumidity stateone humidity form gradually trans-fers to another and therefore consecutively expressedisotherms of adsorption and desorption possess a

Figure 1. Adsorption-desorption isotherms of lime cementplaster, = 1700 kg/m3: experimental, = 20C;calculated, = 10C, 0C, 10C.

flexible Sshaped view. Each material possessesonly for it characteristic such sorption curve.

More detailed examination of the curves showedthat triple moisture-material link exists. The lengthcorresponding to ambient air RH from 0% to 10%is of a slowing rise. In this case, water vapourmoleculescover the walls of material pores and capillaries ini-tially with the layer of monomolecular thickness andthen with the layer of multi-molecular thickness untila water (aqueous) film is formed. Forces of molec-ular attraction act between the material and vapourmolecules, therefore, wet films acquire some proper-ties of a solid body: they do not move or freeze easilyand would not evaporate at standard drying tempera-ture = 105C. The length corresponding to ambientair RH from (1012)% to 45% is still of a slowingrise. Thus adsorbed, vapour molecules maintain ther-modynamic equilibrium, move easily. If the pressureof water vapour in capillaries of the material is higherthan ambient vapour pressure, they get evaporated at105C. The above processes also take place in thelength of a rising straight line from 45% to 55%. Thelength corresponding to ambient air RH from 55%to 100% is of a quickened rise, i.e. material moisturecontent growth picks up speed. In this sorption areathe thermodynamic equilibrium of vapour moleculesis destroyed, because a part of vapour is condensedin capillaries and capillary condensation starts. In the

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length corresponding to ambient air RH from 58%to (7580)% the above action is slow; in that whereinhumidity exceeds 80% the process is intense or veryintense. At this time, a part of themoisture contained inthe material is of a liquid aggregative state. The abovemust be taken into consideration when calculatingmoisture content and heat exchange in the walls. Ther-mal conductivity andmoisture-caused deformations ofthematerial significantly increase in this sorption area.

The investigations indicated that in case of manymaterials initial point of intense capillary condensa-tion was rather distinct, however, in case of somematerials capillary condensation increase is approx-imately proportional to the increase in ambient RH(, %). Material moisture content values (u, %) of theend of intense capillary condensation and on the con-traryof the beginning of intense evaporation (dry-ing) practically coincide irrespective of hysteresis sizeand ambient temperature with exception of negative(below zero) temperatures.

3.1 Group of fine grained structure articles

The above group consists of cement plaster, limecement plaster, masonry mortar, silicate brick articles.

The value of maximum sorption moisture content(umax) is up to 6% (silicate brick). Figure 1 showsadsorption-desorption isotherms of lime cementplaster.

The maximum adsorption-desorption hysteresisu up to120%in comparisonwith sorption isotherm.It corresponds to the range of RHof air = (7580)%(fast moistening, slow drying).

The increase ofmaterialmoisture content from tem-perature is up to 0.30 mass % when temperature dropsfrom 20C to 10C; RH = (4060)%.

3.2 Group of coarse grained structures articles

The above group consists of concrete and expanded-clay concrete articles. The bonding substance iscement.

The value of maximum sorption moisture content(umax) is up to 8% (expanded-clay concrete).

Figure 2 shows adsorption-desorption isotherms ofconcrete.

The maximum adsorption-desorption hysteresisu up to 95% in comparison with sorption isotherm.It corresponds to the range of RHof air = (4070)%(fast moistening, slow drying).

The increase ofmaterialmoisture content from tem-perature is up to 0.50 mass % when temperature dropsfrom 20C to 10C; RH = (6075)%.

3.3 Group of articles of porous structure

This group consists of sub-groups of porous concreteandporous silicate articles. The use of cement and lime

Figure 2. Adsorption-desorption isotherms of concrete, = 2400 kg/m3: experimental, = 20C; calculated, = 10C, 0C, 10C.

bonding material has some specific features. Whencement is used as a bonding material, hysteresis ofadsorption and desorption is 2 times larger than incase of lime use. The most favourable air humidity() environment for the hysteresis of cement articlesis 75%; in case of lime articles 4060%. The abovephenomenon is also observed in case of the articlesof a different structure containing lime: use of limedecreases the hysteresis and the most favourable envi-ronment for its formation is more dry ( 60%)environment.

Summary of the investigation results:

maximum sorption moisture value (umax)up to20%;

maximum adsorption-desorption hysteresis in caseof cement sub-group is in 7580% RH ()environmentu up to +80%; in case of limesub-group4060% in the environmentufrom +9 to +20% (fast drying);

the influence of temperature in the environment ofu4080% RH () is practically the same anddoes not exceed +12% (insignificant).Figure 3 shows adsorption-desorption isotherms of

porous concrete.

3.4 Group of ceramics

The value of maximum sorption moisture content(umax) up to 2.5% (Fig. 4).

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Figure 3. Adsorption-desorption isotherms of porous con-crete, = 600 kg/m3: experimental, = 20C; calculated, = 10C, 0C, 10C.

Figure 4. Adsorption-desorption isotherms of ceramics, = 1700 kg/m3: experimental, = 20C; calculated, = 10C, 0C, 10C.

The maximum adsorption-desorption hysteresisu up to225%in comparisonwith sorption isotherm.It corresponds to the range of RHof air = (6075)%(fast moistening, slow drying).

Figure 5. Adsorption-desorption isotherms of spruce, =500 kg/m3: experimental, = 20C; calculated, = 10C,0C, 10C.

The increase ofmaterialmoisture content from tem-perature is up to 0.14 mass % when temperature dropsfrom 20C to 10C; RH = (5065)%.

3.5 Group of organic structure articles

This group consists of wood articles.The value of maximum sorption moisture content

(umax) up to 28% (Fig. 5).The maximum adsorption-desorption hysteresis

u up to 25% in comparison with sorption isotherm.It corresponds to the range of RHof air = (3080)%(fast moistening, slow drying).

The increase ofmaterialmoisture content from tem-perature is up to 1.8 mass % when temperature dropsfrom 20C to 10C; RH = (3080)%.

4 CONCLUSIONS

It was proved by experimental investigations that char-acteristic points of sorption isotherms indicate thebeginning or the end of changes in the essential physi-cal links ofmaterial andmoisture. Specific parametersof the above changesthe beginning and the endof the process, intensity and linear moisture-causeddeformation of the material, moisture contentarecharacteristic of each structural group of constructionmaterials.

The highest hysteresis in materials of fine structureand porous concrete exists before the beginning of anintense process of capillary condensation at relativehumidity of the ambient air = (7080)%. In case of

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articles of fine-grained structure containing (3035)%and more lime in its bonding material, the mark of thehighest hysteresis shifts to the left by (1015)%; incase of coarse-grained materialsby (1520)% andin case of materials of organic nature by (4050)%.

Temperature influence upon adsorption-desorptionprocess in case of all materials is the highest at relativehumidity of the air close to humidity of the begin-ning of capillary condensation. The absolute value oftemperature influence depends on the nature of theframework of material. The above influence is highestin case coarse-grained, porous and organic materials(3035)%. In all cases, sorption moisture increaseswith decrease in temperature. At high relative humid-ity values and temperature below 0C, material mois-ture u is lower than in isotherms at temperatures abovezero.

The beginning of an intense capillary condensationcan be expressed rather clearly, or start gradually andcontinue in a wide range of ambient humidity. The endof an intense capillary condensation or the beginningof intense capillary evaporation does not depend uponthe size of hysteresis or temperature.

REFERENCES

Bomberg, M.; Haghighat, F.; Grunewald, J. & Plagge, R.2001. Capillary transition point as amaterial characteristicfor HAM models. In Proc. 4th Int. conf. on IAQ, ventila-tion and energy conservation in buildings, 1: 755762.

Carmeliet, J. & Roels, S. 1996. Moisture transfer and dura-bility of open porous media. Proc. of 4th Symposium onBuilding Physics in the Nordic Countries, 2: 587594.Finland.

Carmeliet, J. & Roels, S. 2001. Determination of the isother-malmoisture transport properties of porous buildingmate-rials, Journal of Thermal Envelope&Building Science 24:183210.

Cerny, R.; Drchalova, J.; Hoskova, S. & Toman, J. 1996.Inverse problems of moisture transport in porous materi-als. In Proc. of Second ECCOMAS Conf. on numericalmethods in engineering: 664670. The Netherlands.

EN ISO 12571. 2000. Building materials. Determination ofhygroscopic sorption curves.

Freitas, V.P.; Abrantes, V. & Crausse, P. 1996. Moisturemigration in buildingwallsanalysis of the interface phe-nomena. In Building and Environment, 31(2): 99108.

Hedenblad, G. 1993. Moisture permeability of some porousmaterials. In Proc. of 3rd Symposium on Building Physicsin the Nordic Countries, 2: 697702. Copenhagen.

Lentinen, T. 1996. Capillary moisture transfer in combinedporous building materials. In Proc. 4th Symposium onBuilding Physics in the Nordic Countries, 2: 483490.Finland.

Miniotaite, R. 1998. The durability of finish layers of exter-nal walls of buildings. In Proc. Conference on the sub-ject of Construction and Architecture: 248253. Kaunas:Technology.

Miniotaite, R. 1999a. Compatibility of finishing layer andexternal surface of buildings walls from the standpointof durability. Doctoral Dissertation, Kaunas: Technology.

Miniotaite, R. 1999b. Compatibility of finishing layer andexternal surface of buildings walls from the standpoint ofdurability. Summary of the Thesis for a doctors degree.Kaunas: Technology.

Miniotaite, R. 2004. Hygric properties of several buildingmaterials. InProc. The8 International conferenceModernBuilding Materials, Structures and Techniques: 114119.Vilnius: Technika.

Ramos, N. & Freitas, V. 2006. Evaluation strategy of fin-ishing materials contribution to the hygroscopic inertiaof a room. Research in Building Physics and Build-ing engineeringProceedings of the Third InternationalBuildingPhysicsConference,ConcordiaUniversity,Mon-treal, Canada: 543548.

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Table of contentsPrefaceAcknowledgementsReviewersCommitteesKeynote papersHigh-performance materials in earthquake-resistant concrete bridgesImplications of air pollution on future electricity generationRoot of all evils misunderstanding of construction industry structureConcrete and masonry structuresApplication of nonlinear damper in reinforced concrete structure controlBehavior of cylindrical R/C panel under combined axial and lateral loadCalculation method research on the flexural capacity of PSRC beamCyclic loading deterioration effect in RC moment frames in pushover analysisEvaluating shear capacity of RC joints subjected to cyclic loading using ANNEvaluation of drift distribution in performance-based retrofitting of RC framesExperimental research on high-frequency fatigue behavior of concreteExperimental study of self-centering RC frames with column yielding mechanismExperimental study on high-strength R/C member in tension and shearImproving the behavior of reinforced concrete beams with lap splice reinforcementLoad testing a historic monumentModeling of concrete beams prestressed with AFRP tendonsNonlinear finite element analysis of unbonded post-tensioned concrete beamsPredicting shear strength of cyclically loaded interior beam-column joints using GAsPunching shear strength of RC slabs using lightweight concreteShear strength and deformation prediction in steel fiber RC beamsTorsional resistance of confined brick masonry panelSteel structuresEffect of shear lug on anchor bolt tension in a column base plateElastic-plastic bending load-carrying capacity of steel membersLocal stability and carrying capacity of thin-walled compressed membersFinite element analysis of wind induced buckling of steel tankPerformance based analysis of RBS steel framesPractical non-prismatic stiffness matrix for haunched-rafter pitched-roof steel portal framesRelationship between strength of scaffolds and shear rigidity of framesSequential failure analysis of tension braced MRFsThe optimization of the industrial steel buildingComposite structuresA finite element model for double composite beamA new composite element for FRP-reinforced concrete slabsAn experimental study on double steel-concrete composite beam specimensBehaviour of FRP wrapped circular reinforced concrete columnsContribution of NSM CFRP bars in shear strengthening of concrete membersEffect of transverse reinforcing on circular columns confined with FRPExperimental investigation of FRP wrapped RC circular and square hollow columnsNumerical study on strengthening composite bridgesRepair systems for unbonded post-tensioned 1-way & 2-way slabs with CFRPStrengthening a concrete slab bridge using CFRP compositesStrengthening effect of CCFP for RC member under negative bendingStructural behaviour of reinforced palm kernel shell foamed concrete beamsDynamic impact and earthquake engineeringA note on the model based on the constant Q damping assumption and its corrected modelsA neural-oscillator model for human-induced lateral vibration on footbridgesAnalysis of large dynamic structures in the entertainment industryComparison of different standards for progressive collapse evaluation proceduresCorrelation between minimum building strength and the response modification factorEffect of infill walls in structural response of RC buildingsEstimation of statically equivalent seismic forces of single layer reticular domesExperimental study of RC slab-CFT column connections under seismic deformationsIdentification of frequency dependency of quality factor in subsurface groundIntegrated design and construction to mitigate wind-induced motions of tall buildingsMitigation of high acceleration shock waves in hybrid structuresPrefabricated multi-story structure exposed to engineering seismicitySatisfying drift and acceleration criteria with double FP bearingSeismic analysis of interlocking block in wallfoundationsoil systemShear crack width of RC column with cut-off rebar under cyclic loadingStructural behavior of steel frame connections subjected to blastBridges and special structuresApplicability of AASHTO LRFD live load distribution factors for nonstandard truck loadFull scale test on a bridge PC box girderLong-term deflections of long-span bridgesStructural optimization and computationA revised BESO method for structures with design-dependent gravity loadsInvestigating the buckling behaviour of single layer dome form of space structuresReasoning on structural timber design for target reliabilityShape optimization of shell structures with variable thicknessStructural damage detection in plates using wavelet transformThe non-local theories based on different types of weighted functions and its applicationThe MINLP approach to structural synthesisConstruction materialsBasic study on physical property for calcium-solidification material and on Ca-based concreteCorrelations between filler type and the self compacted concrete propertiesDelphi study on Portland cement concrete specifications of ITDEffects of bamboo material on strength characteristics of calcium-based mortarEffects of remediation and hauling on the air void stability of self-consolidating concreteEstimation of marine salt behavior around the bridge sectionEvaluation of alkali-silica reactivity using aggregate mineralogy and expansion testsEvolution of Portland cement pervious concrete constructionExperimental research on regional confined concrete columns under compressionExperimental study on dry-shrinkage of lightweight cement mortarFlexural behavior of high strength stone dust concreteInfluences of admixtures on performance of roller compacted concreteInvestigation of the effect of aggregate on the performance of permeable concreteInvestigations on flexural behavior of high strength manufactured sane concreteNested ANOVA model applied to evaluate variability of ready-mixed concrete productionOn characteristics of bamboo as structural materialsOptimization of fly ash content in suppressing alkali-silica reactivityOverdosing remediation of plastic SCC exposed to combined hauling time and temperatureResearch into the optimum level of rock-derived micro-fine particles in sand for concreteStrength property of concrete using recycled aggregate and high-volume fly ashStrength, sorptivity and carbonation of geopolymer concreteSuitability of some Ghanaian mineral admixtures for masonry mortar formulationUltra light-weight self consolidating concreteWood use in Type I and II (nonconbustible) constructionComposite materialsComputational models for textile reinforced concrete structuresProperties of natural fiber cement boards for building partitionsStudies on glass fiber reinforced concrete composites - strength and behaviorUse of bamboo composites as structural memebers in building constructionYoung's modulus of newly mixed cementitious extrusion-molded materialsConstruction methodsActive pier underpinning of Jin-bin light rail bridge TianjinCFRP liner quality control for repair of prestressed concrete cylinder pipeConfiguration, evaluation and selection tool (CET) for tunnel construction methodsFormwork specific, process orientated geometrical-path-velocity-time-model (GPVT-model)Open building manufacture systems: A new era for collaboration?Precast ferrocement barrel shell planks as low cost roofTall building boom - now bust?The state-of-the-art of building tallConstruction managementAn anatomy of speculative claims in constructionBuilders' perceptions of the impact of procurement method on project qualityBusiness model of the prefab concrete industry - a two-dimensional cooperation networkConservation project management by the architectural digital photogrammetryConstruction productivity and production rates: Developing countriesContractors' influence within the design process of design-build projectsDelyays in the Iranian construction projects: Stakeholders and economyDesigning the relationship between contractor and client to partnershipDetermining schedule delay causes under the Build-Operate-Transfer model in TaiwanDey Street Tunnel: The challenges of a design project in a congested urban settingDeveloping a document management model for resolving contract disputes for contractorDevelopment of a decision-making model for requirements managementImproving the MEP coordination process through information sharing and establishing trustKey competences of design-build clients in the People's Republic of ChinaPPP-risk identification and allocation model: The crucial success factor for PPPsPrivileges and attractions for private sector involvement in PPP projectsTraining of skills and thinking in structural timber designUse of alternative dispute resolution in construction: A comparative studyConstruction maintenance and infrastructureConstruction safety in the repair and maintenance sectorChallenges of a substation and infrastructue upgrade in an urban downtown settingConstruction of concrete embedded, direct fixation, ballasted, LVT and special trackworkDesign issues of the Palmdale Water Reclamation Plant expansionFuzzy logic based diagnostic tool for management of timber bridgesOrganizational behaviorBehaviors of leadership in architectural officesGendered behavior: Cultures in UK engineering and construction organizationsKnowledge management (KM): 'Integrating past experiences'Managing innovative change within organisations and project team environmentsPersonality types of civil engineers and their roles in team performanceSystem service oriented cooperation - lessons for the construction industrySustainability and energy conservationBuilding environmental assessment toolBuilding passive design and hotel energy efficiencyClimatic effects on building facadesEnergy consumption related to winter housing thermal performanceGreen energy and indoor technologies for smart buildingsIndoor air quality, distribution systems and energy simulationsStructural sustainability of high performance buildingsThe use of green materials in the construction of buildings' structureEngineering economicsAn interactive model for reduction of failure costs: A process management approachForecasting low-cost housing demand in urban area in Malaysia using ANNInfluence of construction costs on schedule performanceLC maintenance strategy development and decision-making model for street maintenanceMacroeconomic costs within the life-cycle of bridgesMaintenance life cycle cost model for drainage systems of infrastructuresTrend analysis of cost performance for public work projectsSmoothing methodology for time series dataUnderlying mechanisms of failure costs in constructionInformation technologyA survey of the curent i-Build practices in the Taiwanese construction industryConstruction information technology and a new age of enlightenmentHow building information modeling has changed the MEP coordination processOrganisational e-readiness in the built environment: People, process, technologyTechnology projects and their impact on the engineering and construction processGeotechnical engineering, foundation and tunnelingDynamic effects of machines on foundations buildingsInvestigations of the dynamic state of turbo sets foundationsModel tests on bearing capacity of soil-bagsThe construction pre-control of a foundation pit in ShanghaiUsing BESO method to optimize the shape reinforcement of underground openingsAuthor indexFlexural behavior of high strength stone dust concreteInfluences of admixtures on performance of roller compacted concreteInvestigation of the effect of aggregate on the performance of permeable concreteInvestigations on flexural behavior of high strength manufactured sane concreteNested ANOVA model applied to evaluate variability of ready-mixed concrete productionOn characteristics of bamboo as structural materialsOptimization of fly ash content in suppressing alkali-silica reactivityOverdosing remediation of plastic SCC exposed to combined hauling time and temperatureResearch into the optimum level of rock-derived micro-fine particles in sand for concreteStrength property of concrete using recycled aggregate and high-volume fly ashStrength, sorptivity and carbonation of geopolymer concreteSuitability of some Ghanaian mineral admixtures for masonry mortar formulationUltra light-weight self consolidating concreteWood use in Type I and II (nonconbustible) constructionComposite materialsComputational models for textile reinforced concrete structuresProperties of natural fiber cement boards for building partitionsStudies on glass fiber reinforced concrete composites - strength and behaviorUse of bamboo composites as structural memebers in building constructionYoung's modulus of newly mixed cementitious extrusion-molded materialsConstruction methodsActive pier underpinning of Jin-bin light rail bridge TianjinCFRP liner quality control for repair of prestressed concrete cylinder pipeConfiguration, evaluation and selection tool (CET) for tunnel construction methodsFormwork specific, process orientated geometrical-path-velocity-time-model (GPVT-model)Open building manufacture systems: A new era for collaboration?Precast ferrocement barrel shell planks as low cost roofTall building boom - now bust?The state-of-the-art of building tallConstruction managementAn anatomy of speculative claims in constructionBuilders' perceptions of the impact of procurement method on project qualityBusiness model of the prefab concrete industry - a two-dimensional cooperation networkConservation project management by the architectural digital photogrammetryConstruction productivity and production rates: Developing countriesContractors' influence within the design process of design-build projectsDelyays in the Iranian construction projects: Stakeholders and economyDesigning the relationship between contractor and client to partnershipDetermining schedule delay causes under the Build-Operate-Transfer model in TaiwanDey Street Tunnel: The challenges of a design project in a congested urban settingDeveloping a document management model for resolving contract disputes for contractorDevelopment of a decision-making model for requirements managementImproving the MEP coordination process through information sharing and establishing trustKey competences of design-build clients in the People's Republic of ChinaPPP-risk identification and allocation model: The crucial success factor for PPPsPrivileges and attractions for private sector involvement in PPP projectsTraining of skills and thinking in structural timber designUse of alternative dispute resolution in construction: A comparative studyConstruction maintenance and infrastructureConstruction safety in the repair and maintenance sectorChallenges of a substation and infrastructue upgrade in an urban downtown settingConstruction of concrete embedded, direct fixation, ballasted, LVT and special trackworkDesign issues of the Palmdale Water Reclamation Plant expansionFuzzy logic based diagnostic tool for management of timber bridgesOrganizational behaviorBehaviors of leadership in architectural officesGendered behavior: Cultures in UK engineering and construction organizationsKnowledge management (KM): 'Integrating past experiences'Managing innovative change within organisations and project team environmentsPersonality types of civil engineers and their roles in team performanceSystem service oriented cooperation - lessons for the construction industrySustainability and energy conservationBuilding environmental assessment toolBuilding passive design and hotel energy efficiencyClimatic effects on building facadesEnergy consumption related to winter housing thermal performanceGreen energy and indoor technologies for smart buildingsIndoor air quality, distribution systems and energy simulationsStructural sustainability of high performance buildingsThe use of green materials in the construction of buildings' structureEngineering economicsAn interactive model for reduction of failure costs: A process management approachForecasting low-cost housing demand in urban area in Malaysia using ANNInfluence of construction costs on schedule performanceLC maintenance strategy development and decision-making model for street maintenanceMacroeconomic costs within the life-cycle of bridgesMaintenance life cycle cost model for drainage systems of infrastructuresTrend analysis of cost performance for public work projectsSmoothing methodology for time series dataUnderlying mechanisms of failure costs in constructionInformation technologyA survey of the curent i-Build practices in the Taiwanese construction industryConstruction information technology and a new age of enlightenmentHow building information modeling has changed the MEP coordination processOrganisational e-readiness in the built environment: People, process, technologyTechnology projects and their impact on the engineering and construction processGeotechnical engineering, foundation and tunnelingDynamic effects of machines on foundations buildingsInvestigations of the dynamic state of turbo sets foundationsModel tests on bearing capacity of soil-bagsThe construction pre-control of a foundation pit in ShanghaiUsing BESO method to optimize the shape reinforcement of underground openingsAuthor index