Instructions for use

Title Dynamic tests on the stability of bituminous mixtures for pavement at low temperature

Author(s) Itakura, Chuzo; Sugawara, Teruo

Citation Memoirs of the Faculty of Engineering, Hokkaido University, 9(4), 575-615

Issue Date 1954-11-18

Doc URL http://hdl.handle.net/2115/37789

Type bulletin (article)

File Information 9(4)_575-616.pdf

Hokkaido University Collection of Scholarly and Academic Papers : HUSCAP

Dynamic Tests on the Stability of Bituminous Mixtures

for Pavement at Low Temperature.

By

Chuzo ITAKURA and Teruo SUGAWARA (Faculty of Engineering, Hokkaido University)

(Received July 25, 1954)

CONTENTS

Synopsis. ......................... 575 Chap. 1 General Description. . . . . . . . . . . . . . . . . 576 Chap. 2 Dynamic tests by Izod and Charpy impact testing machines. 578

Chap. 3 Dynamie test by the modified Page impaet testing maehine. 582

Chap. 4 Freezing and thawing test of bituminous mortar. . . . . 595

Chap. 5 A sonie method of studying the temperature sensitivity of

bituminous mixtures. . . . . . . . . . . . . . . . 601 Chap. 6 Static test by Hubbavd stability test apparatus. . . . . . 608

Chap. 7 Summary and conclusions. . . . . . . . . . . . . . . 612

Acknowledgement......................614 References. ........................ 614

Synopsis

Using several teehniques developed by the authors, determination

was made of the physical pyoperties of bituminous mixtuTes for road

pavement at various low temperatures, the sensitivity o£ mixtures tothose temperatuxes and the resistance against freezing and thawingactions.

Observations were made on the effects of drop hammer impaetusing a modified Page impact testing machine; other dynamic tests

using an Izod and a Charpy impact testing maehines and a sonicapparatus were performed. For･eomparison a Hubbard stabilitystatic test was also made.

As to the results, it has been foupd theq.t the toughness, stab.ility,

and dynamic modulus of elasticity of bituminous mixtures varied ac-

cording to variation of temperature, and each maehine typically in-dicates these eharacteristics, but there were eonsiderable differences

between the dynamic tests and the static tests.

576 Chuzo ITAKuRA and Teruo SUGAWARA

It was found that the sonic apparatus was highly suitable forestimation of stability of bituminous mixtures, and that dynamic tests

were a most reasonable procedure for determination of thecomposition of mixtures in their use for highway pavements. The ultimate objectives of this work in testing of bituminous mix-

tures were to establish suitable proeedures for testing bituminousmixtures at low temperatures, to find out the optimum asphalt content,

to determine bituminous mixtures suitable for pavement in colddistricts and to develop adequate practices for overcoming failures

under the impact of high speed traMc and the other basic damagesdone to pavement in cold weather.

Chapter 1 General description

In eold weather bituminous pavements are extensively damaged bythe frost action and frost heaving of the base and roadbed, change in

physical properties caused by falling of temperature of mixtures,freezing and thawing actions and special winter traMc conditions.

Among these, causes of damages due to base and roadbed werenot taken into eonsideration but those due to properties of surfacecourse were sim. ply considered. Scaling or ravelling of bituminous

pavement damaged by the

Photograph 1Sealing of seal eoat of asphalt concrete.

beating action of chainsattached to pneumatic tires

to prevent the slipping of

running vehicles has been

foundincoldregions. Theamount of this scalingon bituminous pavement,sometimes, may reach toa depth of 2 to 3 cm.Photograph-1 illustrates

damagetotheasphaltpave-ment surface of NationalHighway No. 36, betweenSapporo City and Chitose

Air Port in Hokkaido,Japan. This roadway wasconstructed in 1952 and1953, and has been in

Dyn{,unie [I'e.sts on the Sta,bi,Hty of Bitutr}inous ,Mlixtut'es fot' l't.Lvctnent 577

service for just one winter. This highway pavement is constitutedof asphalt conerete and Topeka; both types of pavement were damaged

by ab.rasion and ravelling caused by the beating action o£ tire chains inwinter. These phenomena suggest both tbe necessity and thesuitability of performing dynamie tes'ts on bituminous mixtures.

The sensitivity of bitu'minous cement and bituminous mixtures is

a most important £actor in their application on highway pavement.It has been reeognized that the bituminous cement and bituminousmixtures are.easily affected, as to their ehemical constitution and

physical and mechanical properties, by temperature variation. More-over i't.is recognized that the range gf this temperature variation within

which the mechanical properties of mixtures make,them ideally available

for pavement purposes are within not more than 300C･to 400C.

In general the toughness of bituminous mixtures is transformedinto brittleness as temperature drbps. The mixtures show liquid pro-perties dt temperatures higher than 300C to 400C, plastic properties at

moclerate temperatures and elastie or brittle at lower than about 50C,

For the analysis of rheological properties of bituminous cement,

conventional methods have been developed. They include,the deter-

mination of softening point and penetration. The so£tening point isthe temperature at which the mixture possesses a. consistency con-foyming to eonventional standard, sueh as the Ring.and Ball method.

The penetration is,the depth to which the need]e .of standard sizepenetrates into bitumen within specifed time under a standard loadat given temperature, The ductility,, and others have also been usedto measure the rheological pyoperties,of bituminous cement.

, Some methods')2) coneerned with the determination of the tem-perature sensitivity of bituminous cement sueh as "Penetration Index"

based upon penetability, have also been presented.

Several methods and apparatuses for determining the stability or

temperature sensitivity of bituminous mixture have been offered, but

these techniques are not always adequate for the explanation ofproperties of highway materials because they are static tests.

Several methods and apparatuses for explanation of properties of

bituminous mixtures as affected by temperature variation were triedby the authors, Observations were made on the effect of drop hammerimpact in wh2eh use was made of a Page impact testing machine. Othey dynamic tests weye made using an Izod and a ,Charpy impact testing

maehines, and a sonic apparatus. On the other hand for comparison, a

578 Chuzo l'rAI<URA and Teruo SuGAWARA

Hubbayd stability static te$t and compression tests weye made.

ChaPter Z teDttYirniarrAt Cactfi?,ksesb.y Izod and Charpy impact

1.. Apparatuses and preparation of specimens.

(1) Impact shear test with Izod testing machine.

An Izod impact testing machine with a 20 kg.cm eapaeity was used.

The pendu}um consi$ts of a hammer weighing 1.205kg with a pivotswinging in ball bearings in a vertical stand that is bolted down toa east iron bed plate, The pendulum strikes against a specimen, which

is clamped to act as a vertical eantilever, but in this test the clamping

equipment was reconstructed in order to make clear te develop thedynamic shearing action.

If frietion losses in the swinging pivot are not considered, the

feonlelorwgg:COnSUMed in rupturing the speeimen may be. computed as

, Initialenergy=WH=WR(l-eosA) ' Energy after a speeimen ruptures == WH'=WR (l-eosB) Energy to rupture ,a speeimen = IiV (El-H') =-(WR)(cos B-cos .4)

wherel W:weight･ofpendulum. ･ H:･ height of fall of ･center of gxavity of pendulum.

H': height of rise of eenter of pendulum after hitting

a specimen. A: angle of fall.

B: angle o£ yise. R: distance from center of gravity of pendulum to axis

of swing O.

The principle of this testing machine is shown in Fig. 1.

(2) Impact fiexure test with Chaypy testing maehine.

A Charpy impact testing machine having capacity of about 30kg.cm was used. The prineiple of this machine is illustrated in Fig. 2.

./ The pendulum consists of a relatively light but rigid bar on the

end o£ which is a heavy-disc; the pendulum is suspended from a sh6rtshaft that rotates in ball bearings and swings midway between tworigid ･upright stands, close to the base of which the specimen issupported on an anvil. The fiexural test speeimen mounted on the$upport ptceepts the impact energy o/ff the pendulum at the bottom o.f. a

Dynamie Tests on the Stability' of,Bituminous Mixtutes for Pavement

cE:gvaRRGOF

o,

BS.LA R . CENTEROpuMASS ANGLE OF OE FALL

ATIGLE' OF RrsE

×× H'

w Fig. 1

notch cut in

mortar were

(3)

Asphalt:

,

1

･!

PENr)Uturt

'

/ W

l'-x /x .iiJ/F.:'IC,,N,Nl

Staviek. /-! 1 Poihfer.... Aentn,lum

H

6fundond . '

× s..... Anw7-

)tsvkthgr

en9e. -------

./ {5bectlnen

579

1

,.,;' 1

//

'Spaeerelationforpendulum ' t t. maehine. ' Fig,Z Charpy impact testing maehine

' it.' As specimens, 25 by 15 by 90mm pieces of asphalt

prepared,

In these experiments two kinds of aspha}t, Trinidad Lake asphalt and Akita straight asphalt produeed in Akita, Japan, were used; their eharacteristics are

shown in Table-1, .･. ' ' TtxBm7. 1 Characteristics of bituminous cement

Items

III

l.

Trinidad Lake asphalt

Specific gravity

Softening point

Penetration at

Ductility

250C

1.212

410C

37

24 <15eC)

Al{ita straight asphalt

1,O03

36VC

.101

14 (50C)･

Sand : C.rushed quartz sand having specific gravity 2.63,'and the gi.`ading oli which 99% passes O.3mm sieve, ancl is

-retattnecl on O.Z5mm sieve. ･

Composition: As shown in Table 2,

580 ChUzo ITAKURA and'Teruo ･SUGAWARA

[lrABTtE 2 [I]he composition.of bituminous mixtures

No.'

1

2

3

4

5

6

7

8

Asphalt content

by weight (%)

5,O

7.5

10.0

12.5

15D

20.0

50.0

100

by volume (%)Trinidad 'l Akita

10.2

15.0

19.5

23.6

27.7

35,2

68.5

100

12.2

17.6

22.6

27.3

31.7

39.7

72.5

100

Sand eontent

by weight (%)

95.0

92.5

90.0

87.5

85,O

80.0

50.0

o

by volume (%)Trinidad r Akita

898

85.0

80.5

76.4

72.3

64,8

31.5

ox

87.8

82.4

77.4

72.7

68.3

60.3

27.5

o

(4) Preparation of specimens, , The specimens were molded in a steel framed form.･ All speeimens

were pressed under a load intensity of 8kg per sq cm, by Amstlarcompression testing maehine of 500 kg capacity;

2. Test results･

The impact tests of asphalt mixtures were made at 10 differenttemperatures: -200C, -150C, -100C, -50C,. OOC, 50C, loOC, lsOC, 2ooC,

300C. At lower than OOC the specimens were thoroughly eooled in a

low temperature room. Test results by an Izod and a Charpy impact testing machines are

shown in [I]able-3 and Table-L4. [l]he asphalt content o£ mixture havingmaximum absorbed energy measured by the Izod impact testing

maehine was 15% asphalt content at test temperature o£ 300C; 20% attest temperatures of 200, 100, 50, -100, -150 and -200C; and 5e% at OOC.

As the result the optimum asphalt content measured by the Izodwas determined to be 20% at the various temperatures. At the vari-ous test temperatures, 'the maximum absorbed energy of each mixture

was, O.647 kg.emlcm2 on 5%, 1.197 kg.emlcm2 on 7,5%, 1.783 kg.cm/cmL'

on 10%, 4,830 1<g,cmlcm2 on 15%, at test temperature of 300C･; 1.707

kg.cmlcm2 on 12.5% at 50C; 3.703 kg,cmlcmfl on 20%, 3.220 kg.cmlcmL' on

50% and 1.583kg.emlcm2 on 100% at 200C. On the last three of 20%,50% and 100% mixtures, the absoTbedenergy could not be determined

at300C. Then the mixtuxe having 20% asphal't except th.ree kinds o:£eompositions above mentioned which might not be usable in field, may

have the maximum absorbed energy.

Dynamie Tests of the Stabili'ty of Bituminous Mixtures for Pavement 581

[I]ABIJE 3 Absorbed energy of

temperature by an

bituminous

Izod impact

mortar at each

testing machine

AsphaltI

content

(%)

5.0

7,5

10.0

12.5

15.0

2o.o

50.0

100.0

Absorbed energy at each temperature kg..em/cme

30 OCE 20 OCl

O.647

1.197

1.783

1.643

4.830

O.603

O.923

1.410

1.277

2.570

3.703

3.220

1.583

15 OC

O.540

O.900

1.560

1.473

.2.260

3.343

1.843

1.070

10 OC

O.643

1.057

･1.467

1.657

2.123

2,210

1.610

O.923

5 eC

O.617

1.000

1.390

Z707

1.720

2.623

1.683

O.973

ooc I- soc

O.540

O.773

1.360

1.680

1.930

1.717

i,820･

O.687

O.537

O.750

1.340

i.497

1.793

2.067

1.093

O.683

-10 OC

O.580

O.910

1.187

1.430

2,137

2.330

1,377

O.580･

-15 OC

O.567

O.813

1.067

O.910

1.880

1.907･

1.843

O.413

-20 OC

O.400

O.693

O,893

O.720

1.310

1.457

1.197

O.520

TABTJE 4 Absorbed energy o£ bituminous mortaT at each temperature by a Charpy imp4ct testing machine

Asphalti

eontent I"

(.O!.) i

Absorbed energy at eaeh temperature kg.em,lcmL'

3o ec i 20 "c

5,O

7.5

10,O

12.5

15.0

20.0

50,O

100.0

O,920

1.497

1.060

1.170

2,630

3,143

O.803

O,980

1.146

1.510

1.810

4.360

4.630

1510

15 C'C

1.666

1.500

1.100

1.810･

1,465

1.423

lo ec

O.993

1.220

2,170

1.453

1.690

2.143

1.610

1.140

5 OC

O.993

1,100

1.493

2.139

2.353

1.770

1.010

1.150

o oc

1,067

O.889

1,533

2.960

1.453

1.733

.1.170

1.180

I- 5"Ci-10 bC

i

1.303 '

1,260

1.916

2.140

1.650

1,223

1.110

lLl

1.19e

1.260

1,570

1.609

1,413

2,686

1.743

1.066

- is ocl-2o oc

1.067

1.220

1,533

1.453

1.410

1.970

1.4g3

O.840

O.953

4.132

1.570

O.960

1.613

1.050

2.283

O.950

In the tests using the Charpy impaet testing machine, the regular

relation of asphalt content and composition could not be obtained, but

the absorbed ene]rgy showed the higher value than on the Izod testing

machine, by the amount o£ approximately 20%, and these values havethe same 'tendency as those obtai,necl. by the Izod test, ,i,e, tl}e mixtuire

having, maximum abso.rbecl ene.vgy at eaeh test 'teml,)eratui'e was 20%

asphalt eontent excepting a few cases.

582 Chuzo ITAKURA and Tervo SUGAwARA

Chapter 3 Dynamic test by a modified Page impact testing machine.

1･ Apparatus3).

A Page impaet testing machine used for measuring the toughnessof stones was reconstructed to make it suitable in type and capacity

for,deter.mining the,brittleness of bituminous mixtures. The Pageimpact testing machine commonly used for determining the brittleness

of stones.has a drop hammer weighing 2kg. However this hammescweight is too large for tests of the bituminous mixtures, so it was

reduced to 710gr. The apparatus was arranged so that the hammer

weight £all £reely between suitable guides, A plunger made ofhardend steel with spherical sur£aee, was placed directly on thespecimen. In the test a speeimen immeysed in a small water bath for

temperature contro} was put on a steel anvil. Specimens were l<eptfor several hours in a water bath as desired test temperature and'care was taken to make sure that they were 10 uniform temperaturesthroughout. The 710 gr. hammer was released by a tripping mechanism

and its falling height was increased by 1em each time when it wasdropped,

It was considered a £ailure of the specimens if they broke intotwo or three pieces at low temperature, while it was so eonsideredwhen remarkable deformation of speeimen tool< place at high tempera-

ture. Judgement of the oceurrence of such failure was rather diMeult

problem, so the reliability in accuracy of toughness value was low at

300C on mixtuxe with richer than 20% in asphalt content on account

of diMeulty o£ rneasurement at that temperature. When the failureo£ breaking or deformation at which cracking occurred on specimen,was recorded. Those values were taken to indieate the brittleness of

the speeimens.

2. Preparation of the specimems.

Materials and composition of specimens was the same as that ofspecimens used in the Izod and the Charpy impact test, The size ofspecimen was determined aecording to the capacity of the testingmachine, after the tests on selection of the suitable size. As the result

the specimens in the form 35mm¢×30mm cylinder was used. Theforms were made of steel pipe, and steel bar was used £or pressingof mixture and removing the speeimen, All specimens were pressedunder a Ioad intensity of 8kg per sq.em, This loac'{ intensity was

Dynamic Tests on the Stability of Bituminous Mixtures for Pavement 583

eonsidered the same as thatproduced with a road-roller onroad paving in a field project.

All specimens removed from theform, were stored in low tem-perature room in which thetemperature was maintained atOOC untilthe test. Photograph-2 shows the molding and remov-ing devices.

3. Test results.

The impact tests of mix-tures were made at 10 different

temperatures: -200, -150,-loo, -- se, oQ, so, loo, lso, 2oo,

throughly cooled in a low

are shown in Fig. 3-Fig. 12,Fig. 30-Fig. 36.

Fig. 3-Fig. 12 show thetoughness on Trinidad Lakethat on Akita straight asphalt.

between test temperature andTrinidad Lake asphaltAkita straight asphalt mixtures,

4. Cenclusien`

From the above tests byfollowing conclusions were

(1) Although the hardness

i"' '"' t''

I,-f,･,

･///

tt ]tt

..g;/.tlt.:.//-i'.-t-.1'l/-"ft.tErl-i/l.11/'.',.i.ttt,}:i.tl.tt".. t-"' '

' ,･tt-ee･ ･--

",l･.･'--･-･=./--･'･･.I･z-g･-

fl}il.

300C,

temperature Fig.

ee..pmc.;iv See.

Phetograph 2 Molding device and removing deviee.

at lower than OOC the specimens

room. Results of these tests13-Fig. 22, Fig. 23-Fig. 29 and

relationship of asphalt content and asphalt mixtures, Fig. 13-Fig. 22 show Fig. 23-Fig. 29 shows the relation

toughness at each temperature onmixtures, and Fig. 30-Fig. 36 show that on respectively.

the Page impact testing maehine the reached. was inereased in both Trinidad Lakeasphalt and Akita straight asphalt, the toughness was generally reduced

in aecordanee with lowering of temperature as shown in the Figures;

in some temperature variation ranges, these reduction rates ofbrittleness showed the parabolic relation. Although general shapesof relationship between temperature and toughness were the same ineach composition as shown in Fig. 23--Fig. 36, there were considerable

differenees in absolute value of toughness in each composition of mix-

tures. The temperature range in which the relation between toughness

and temperature shows the parabolic relation was higher than 5"C but

lower than normal atmospheric temperature.

oroopt

Fig･ 3-Fig. IZ Relation between asphalt content and toughness of Akita

asphalt by the modified Page impaet testing maehine.

Y:Toughness. X:Asphaltcontentinpereent.

straighr

mmpt

Zmepob

70

60

50

40

30

2e

10

e

A-lTESTTEMP.:-200C

7=0-90Z<2o%

--L..-..'----'---.

e

20 50ASPHALT

Fig. 3CONTENT (%)

ICa

70

60

co 50es

: 40

gg 3o

20

10

o

n-2TESTTEMp.-lsOC

3=l./2z<2o%

1"-se..--

o oo

ss--li

20 50ASPHALT CONTENT {%)

Fig. 4

100

orrfi

NoHe>xapa

>pa

:QEony

go･

ua¢

Q>$>pa

>

70

ee

ec sea:

Nz･

:･ 4eopos 3o

20

z.o

o

7･O

60

5･Oa･co,

N,

Z <e=i

epo s.a･E-1

RO

1'O

o

A-5TESTTEM?.-loOc

y==/.12.z'<2a%

'

"---"--s--

e

-

10 20 50A'SPHALT CONTENT ('%)

Fig. 5

100

A-5ll'TESTTEMP.:oac

' Y=L59Z<2P%

j

;e

e

90 tioA$PHAt[g.CONTENT (%)

Fig. 7

100

70

60

op 50cora

Zpt 40g2- 3o

20

ao

A-4'

TESTTE"t[?.:-sec

dV--1./8X<20%

'

,

eL----.----.

'

'

o

70

60

50cacofl

z 40g8 3ots

20

ao

o

2e 50ASPHALT

Fig. 6

CONTST C%)100

A-6 TESTTEMP.:5PG

7=!-67Z<2o%

tt

--tnet.tttT

L--

tt

eo ---

o l

o

io

AS?HALT

Yig. 8

CONTENT (%)

wtc5pB.-'

aoU)

emoes

sc5ge

g=･x'sc

oth

scg'gg-rr-･

2ua

gN'

axmthoNrepo

<oHorr

et

enooca

coeneq

zrt

opots

'h

,s

cacopa

ztu

epo-

ro

60

50

40

80

20

10

o

70

60

50

40

3' O

20

;o

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A-7TESTTEIfP.:leOc

7==1.73,Z<2o%'

rs.--t-.------s

18Pep

o

2e

ASPHALT

Fig.

se

CONTENT (%}

9

100

A-9 1 reST rvEMP.,

2CPC

t-st S-L

7- z.2gr <70%

ss ss-

l･li,g

1

/･

:.

/-

f /

20 50 ID

ASPHALT

Fig. Ia

CONTENT (%)

70

60

50mua

mz 4erc

gg 30

20

ao

o

mopva

zopoe

A-8TESTTEMp.:aS"G

7=2.03Z<2o%lttt..t.

2

'

'

ASPHALT

Fig.

CONTENT (%)

le

A-lemeSTTEId?:30eo

nZt3.00Z<20'%

7e

60

50

40

30

20

10

o

'

o

ASPllALT

Fig. gzCONTENT t%)

ptooa

otrst

NoHe>xax>pa

=mu

sony

go･uaao>$>ra

>

7e

60

50:.

S 4o

E 3o

2e

10

e･

ljig. S3asig. ZZ Rellation between asphalt content and toughness of Trinidad Lake asphalt

by the modified Page impaet teseing machine.

Y: Toughnessateaehtemperature. X: Asphaltcontentinpereent.

iil7,-f[t./lTTESTTE)P.:-2o"e

/Il }=1.17Z<20%'t'

Il, "------h'-

/1lett-.

"i'itr'il

'

20 seASPHALT

Fig. N3

CONTENr (%)leo

70

60

:t 50

:.v 4o

g 30

20

10

･o

･T-2 '

TeST[rEM?.:-15"C

3==L/2X<2o%

e

g

'

'

20 5QS+SPHALT CONTENT(%)

Fig. 14

aoo

vtc=ge

g5'

so"1ttua

o:cttrouaegev=p'Kotr

g.

g:.

gbi

g.

t#'

[9oth

ny

rege

<oso=ct

etco"

70

6eg tt'oc;･

ttt

mz 4･O=-･

o'=o sob

2ei'

to

mmmzpt

opob

e

7Q

60

50

4e

ll.-,

TESTTEMP.-100c

/･

e

'.------------

fiilo.

I/o

3el

20P

io

a

2e 50ASPHALTCONTENT C%') Fig. i5

ioo

TLv=

TRSTTEMP,:oac]=1.21X<20%

r'

p

ID

AS?HALT CONTENT C%)

Fig. a7

70

6a

50mm･mZ 30glg '3o

e 20

10

e

70

60

somco

M 40zmoD eooB 20

IO

g

7-4:

10BSTTEM?.:-5"Ctt

7=L37X<ze%

t'--"

e

h-----

'

'o

20 seA,SPHALT CONTENT f%)

Fig. 16

1ca

7-6TESTTEMP.:5℃

'

7TL,35Z<20%

"----------.1

oo

20 bOASPHALW CONTENT (%)

Fig. 18

iee

engg

ocrsNo-Hfi>xcpa.

>ge･

=n-9gto

ao>$>x>

envapt

ztu

cr

poe

cocapt,

zva

opots

70

6e

se

40

3g

20

ae

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/

T-7TESTTEM?.:10eC

1"-'-'"---3=!･SIZ<zp%

o

.e'

AsPSALir coNTENT (%) '

' Fig. 19

70

eo7-9 rh---'1'"'-.'

.'- STTE)eg?:2oec

5b.v=z.lo.x<?a･

40

30

o

m

t/

20

le

eASPgALT CONTENT (%)

tt Fig. 21

70

6e

50:.

ztu 4e

go 3eig/･.

2e

i9.

9-

80

BO

mmM 50znc

o 40pop 30

20

le

g

T-8TEST TEMP. : 150C

----- . g=Leoz <zo%

-

20 se

'ASPHALT CONdiENT

Fig. 20(%)

leo

T-leTESTTE'M?.:BGOCg=3.bzx' <2o%

o

'

e

-.t

'

'

ua 5oAS?HAI,T CONTENT

Fig. 2Z

(%)100

v tc ,IJ ptv'

- g.

o e r. 2 ta

9 - e-r.

5 va rt =- =- f' e. sc

o ･wo

x f' fi -= =･ = 9 et

g N' rre 6 U2 '-l9

･,v 1. A b'

: -r c'r

･;p

on,---

590 Chuzo I'rAI<uRA n.nd Ter-o SUC;AWA}?.A

Fig. Z3 --Fig. Z9

Relation between test temperature

and toughness of Akita straight

asphalt by the modified Page impaet

testing machine,

(percent shows the asphale content)

eauara

ztwcr

pQ･-tw

A-1 s%70

60

50

4e

30

2

10

.

'

-20 -10 O Xew 20 TEMPERATVRma Fig. 23

3e℃･

encaeq

ztu

eb'o

p

A-2 7.S%

4e

70

60

50

30

2'

1 o '

-- 2O -xo o le 2o TMMPERATURE Fig. 24

3eoC'

eacapa

Ztuca

pop

70

60Am4 /e.s%

50

40 .

30

2 o .

8 o

10

.2. 0 -10 O 10 maMPMRATURM Fig. 2S

20 30 oC'

eauapm

zcu

eig

olv

Dynamic Tests on the Stability. of Bituminous Mixtuves for Pavement

A-3 10%7U

60

50

40

30

o

o8

eo

¥- 2O

kk 4o

go 3etw

$6

-lo o lo 2o 3e TEMPERATURM ℃, Fig. 26

oAr6' 20%

f'

oo

o

o･

-2o -xo e xQ 2o TEMPERATUftE

Fig. Z8

geeC･

swen

tucu

he

oju

eauapa

zpt

etb

odv

591

70

80A-･5 !5%

JrO

'

40

3e

20

10

o.

oo O

-2o -lo e lo 2o TEMPERATURE Fig. Z7

30℃ny

70

60A-7 so%

se

4e o

32010

.

8o

-20 --XO o ze 2o 3cTEMPERATURE `l:,

Fig. 29

592 Cl'!uzo !."i'AK.vii:.A amd Teifuo STIGA.XVAI.1.A

Fig. 30-Fig. 36Relation between test temperature

and toughness of Trinidad Lake

asphalt by the modified ?age impaet

testing maehine.

(percent shows the asphalt eonte4t)

uarnpmti

an

oto

cois

7--1 5%70

60

50

40

30

21

.

.

t}

-20 -so ･e lo 2o. TEMPERATIIrRW Fig. 30

･3ew

℃

cocopm

zptcoto

otw

70r-z 75%

60

56

40

so

20o

x .

-20 -10 O 10 20 30 TEMPERATURE `t. Fig･ 31

･ea

enpm

zpa

ot'

oju

7-3 le%i

70

60

50

40

30

o

oooo

o

--20 -SO O iO 20 SO･ TEMPERATURE `t. Fig･ 3Z

/Dynamie Te,)ts on the Stability o.f Bituminous Mixtures for Pavement 593

eaonpm

z

o.p

oju

th

pm

ztwer

poju

T--4 /2.S%

7e

60

50

40

3es

20

8o

1

-20 -xo e xo 2Q 3e TSMPERATURE ℃, Fig. 33

70"r-6 2e%

60

50

g

`NO

30

20

10

o

8

o

-20 -to O 10. 20 TE'TV[PERATV'RE

Fig. 3S

30

℃

/co･ua

pm･z･

twes

poe

mcopm

zpa

o)

･otw

r-s IS%l70

60

50

40

30

20

10

B.

oo

o

-eo '"iO O SO 20 SOTEM･PERAiPV'RM ℃.

Hg. 34

o70

7-7 so%

6' o

50

40

o.o

8

o30

20

1･

o

-2e -io 6 lo 2o TEMPERATURva Fig. 36

30oC'

594 Chuzo l'rAKuRA and Teruo SuGAwA]<A

(2) The values of 'tough.ness ratio at the two different testtemperatures 200C and OOC were ealculated. These values of toughness

ratio were O.67 oR 5%, O.53 on 7.5%, O.52 on 10%, O.61 on 12,5%, O.58

on 15%, O.59 on 20% and O.51 on 50% in mixtures made of TrinidadLake asphalt. On mixtures made of Akita straight asphalt the valueswere O.60 on 5%, O.67 on 7.5%, O.56 on 10%, O,65 on 12.5%, O.63 on15%, O.61 on 20% and O.49 on 50%. 'As shown in the above, there were no considerable differences onvalues of toughness ratio calculated at the two different temperatures,

and this range of these values was between O.49 and O.67. These facts show that the temperature sensitivity of mixturesdepends on temperature sensitivity of bituminous eement, and toughness

ratio (referred as to log. penetration Index) at two different tempera-

tures did not vary although any composition of mixtures was selected.

Piurther, there were no remarkable differences in log. toughness-tem-

perature slopes. Then if high stability at some high or low tempera-

tuye is wanted, the bituminous cement having Iow sensitivity should be

selected; the high stability can not be obtainect without the seieetion

of an appreeiate bituminous eement.

(3) The mix'tures generally showed viseous-liquid properties at

temperatures higher than normal atmospherie temperatures in summey,and the temperatures in the mixtures attained 'the maxi-mum toughness

were different in each specimen. These temperatures may depend oncompositions, in fact the relation of bituminous content and temperature

resulting in the maximum toughness, showed a regula,r relation ineach. This temperature limit was higher in specimens with richasphalt content than in those with lowez' asphalt content.

(4) A value of toughness of Trinidad Lake asphalt mixtures washigher than those of Akita straight a,sphalt at ].ower than O"C onmixtures constituted of lower than 20% asphalt eontent.

(5) In proportion to asphalt content the toughness inereased within

a certain range of asphalt content; the limits were 20 to 25% in both

kinds of asphalt, but at points higher than this limit the toughness

was redueed. (6) At lower than 50C the mixtures, generally,showed a non-plastic

eharaeter. ' (7)'`) It was found that the elastieity infiueneed the relationship

between pene't.ration and temperature. It vgras also found that thedifferences in the slopes of penetra'eion-tempez'ature linesi) in semi-log.

l;ynamieTefstsontt!teStahilityofBitttrninousMixturegt'orPa,vemenC 595

scale shown in bitumens of different types were principally determined

by 'this property. This means that the eharaeterization of the bitUmen

aeeording to its rheologieal type ean also be based on the slope of the

log. penetration-temperature curves. So this slope was expressed byan Index 'figure, the penetration index. In these tests of bituminous

mixtures, shnilaTIy, the same regular toughness relation were obtained

withln certain ranges of temperature,

･ Finally it may be said that these test may be satisfaetorily usedfor determination of stability and tempera･ture sensitivity of bituminous

mixtures. Espeeial]y, the Page impact testing maehine elearly showsthe value of stabllity.' In these experiments, tests of bituminous Mortar

only were made, and if a･'suitable Page impact testing machine havinglarger capaeity can be provided, the stability of asphalt conerete and

other mater!als may surely be determined'satisfactorily.

Chapter. 4 Freezing and thawing test of bituminous rnortar.

For tests the Page impact testing machine was used to determine

the resisting power o£ bituminous mixtures against freezing andthawing. Although bitvnninous mixtures have commonly been regarded asnon-absorbing material, it has been made clear5) that some 1<inds of

bitumen absorb considerab16 quantities of water. Bitumen may be

considesced 'to absorb the water in the £ollowing ways: a. Bitumen is generally soluble in water even in small amount.

b. If water soluble are contained in bitumen, the salt will bedissolved in water and water will entrain in bitumen itself,

c. As the result of presence SIZE OP. .S?ECIMEN 2-5xl.5x9.'O cm 2.5xl.5x9.0 cm 3:Ze:3:8 c.:

gv.

&9,

ee

1･;

L'

'v'

fi.;

a

7

6

s

4

o

z

l

e

ptpt-

KINDOPAspHAI,T

TRINIDAPr,TRAIGHTTRINIDAD'S'VRAIGHTr

-- --

I,

pt.-N

"Ys

.

l,SSO,T.S taote,slsoITseae

Relation

and

mens

A3PHasTCONTENrS $

Fig. 37 between asphalt contentpercent of absorption of speci-

after 96 hours immersion.

of fi11er in bitumen.

Of the above three ways thelast two occur to a considerable

degree. Furthermore the waterabsorption of bituminous mixtures

may be increased by the presenceof fi'ne and eearse aggregates. It

is not at all hard to understand

that the durability under theinfiuence of freezing and thawing

aetions is reduced proportionally

with increase o£ water absorption.

596 Chuzol'rfv<uRix 4nd Teruo S(JGAwARA

Kaving these points in mind, the present freezing and thawing tests

were made. The eompositions and other ehascacters of specimens aresimilar to those used in the dynamie test with the Page impact testing

machi,ne, The speeimens made of two kinds of asphalt, Akita andTrinidad, were immersed in water of iOOC before tests. After 96hours immez'sion, specimens were taken out from the water bath andthe surface water was wiped off with a clean towel. Specimen weighed;

the weight Qf speeirnen vvas inereased by soaking in water, then it

was assumed ･that the weight increase was due to･absorption. Fig. 37 shows the relation beeween bituminous content and per-

cent o£ absorption, after 96 hours' immersion. Speeimens were frozenin low temperature room in which the temperature was maintainedat -150C to -209C, for 1.5 hours, and they were thawed in water of100C, and these proeedures were repeated. The weight and toughnesswere measured at 10, 20, 30, 40, 50 and 60 eyeles of freezing andthawing; the toughness testings were made at temperature of 100C in

all speeimens. The toughness were determined -by the Page impaettesting machine, aceordingly the toughness val'tie is indicated by a drop

height. F{g. 38 and Fig. 39 show the relation of weight vari.ation a,nd

cyeles of Ereezing and thawing o£ the specimen of each l<ind ot com-position. In these Figues each axis shows the weight variation based

on initial reacting of weight of each mixtures and eycles of freezing

i.79

1.10

1.00

IL,

15

2e

50

Fig･-, lo 2o 3o 4o se 38 Relation Between variation of weight of

straight asphalt mortar and eyeles of

freezing and thawing'.

pa

f

pt

,5 X

%

s

,! 100 pt

Akit,a

Dynarnic Tests on the Stability' of Bitumlnous Mixtuves for Pavement 597

and thawing. Fig. 40 and Fig. 41 show how the toughness isby freezing and thawing. Table--5 is a tabulation of theseFrom these tests the following conclusions were attained.

affected

results.

1.IO･

In

Rkd

k. 1･10

'M

o::[<.

>

i.oo

5S7.5k'

io$12.5pt

i5X

EOS

JroU

o IO 20 50 cyCllEs oF FReEzlNd

40

AND THAWING

50 60

100 pt

Fig, 39 Relation between variation of weight of

Lake asphalt mortav and eycles of

freezing and thawing.

'rrinldad

50

4o

as.

eosfl

te1

:ntn 20

)o

e

× sog23.h'

15%

zz

12.5$'

io'A100/,

7,ropu'

5al

IO 20 30cycLEs oF l"ftr･;Ezrr;G AtaD

40W{A'NJN･1

se

F;g. 40 Relation between toughness of Akita straighl]

mortatr and eycles o£ freezing and thawing.

(by page impaet testing maehine)

asphaH)

598 Chuzo ITAI<vRA and Teruo SUGAWARA

60

50

40

g-

L' 30Fl.

st

L.･}

s･

X 2o

IO

50S

100fi"

2Qpt

-$r

,5pt

fi･

.5Spt

l5va

IO

75

T-tt tn4Atu.mmp

O IO EO :o 40 ･50 60 CYCLES OF F'REEZrm. kND THA?irNl)

Fig. 41 Relation between toughenss of [{)rinidad Lal<e asphalt

mortar and eyeles of freezing and thawing.

(by Page'impact testing machine)

1. Variation of weight.

a) The water absorption of bituminous mortar was, to certain extent, inversely proportional to bituminous eontent.

b) The rate of weight increase was rather rapid within 30 cycles of freezing and thawing. The weight increase showed a constant pro- portion in the Akita straight asphalt mixtures.

e) There were no remarkable weight variations caused by freezings

and thawings, in either bituminous cement or in mixtures eonstituted of 50% bituminous cement, but such phenomena did not alvsTayS indicate

the non-absorbing character, because the specific gravity of bituminous

cement is quite elose to that of water.

d) In these tests only 60 cyeles of ,freezing and thawing test were

made, but if these actions are repeated more times, it may be con- eluded that the weight inerease would surely be greater.

' e)Astheweigh'tofmix'turesincreasesbecauseo,fwaterabsorp- tion or beeause of fireezing and thawing aetioi), the 'textux'e of the

mixtures becomes rough. This phenomeno'nindicates 'th.atthe durability

may be affected by that aetion.

[g]A.BT,E 5

1l

i i-Asphalt ,

content -

Weight variation

Ki]).sT,/ o/f AsphaltCYWc'1'e'o o'f

andoI io

f'r6ezing and 'ffawin.cr

wel. tLht ver]atif .n....

20 30 40 so l 6o'

il

1Cyeles of freezing and thawing percent of weight variation

and

:

L

;;il

i

i

5D

7.5

4.0

(o)

3.5

(o)

- 2.4

(o)

2.5

(o)

i 1.6

(o)

i O.8

(o)

l 8.0

i (4 0)

I 7.0

(3.5)

4.4

(2.0)

4.0

(2.0)

3.4

(1.8>

1.8

Cl O)

d

lE

14.0

CIO.O)

13.2

{9.7)

9.0

(6.6)

8.5

(6 5)

7.0

(5.4)

2.7

(1.9)

o

T, rinidad

Lak,e Asphalt

l1

10.0

12 5

15.0

20.0ll

I

f l

i

17.2

(13.2)

16 2

(12,7)

11.4

(9 O)

11.0

(90)

9.6

(8.0)

32(2.4)

'lI

i

i

r

1

l::

18.0

f14.0)

17.0

(13.5)

12.6

(10 2)

12.2

(10.2)

10.8

<9.2)

3.4

(2.6)

l

I

;

18.4

C14.4)

17.2

C13.7)

13.6

(11.2)

13.2

(11.2)

11.2

(9.6)

3.5

(2.7)

sl 18.8i C14.8)

17.5

(14,O).

14.1

(11.7)

l3.6

(11.6)

al.4

E (9.8)

3.6

(2.8)

'

liill

1

1

1

1

10 , 20 i 30 l 40 i 50 I 60

2.ooI3so 4.30

i' i2,eo i 3m7 [ 4.6o

1.83 ii 3.75

l

2.00 4.25 I

213 4,38 l

2.25 3.38

I

4.75

I

[ 3.50

4.86

5.25 I i L5,50 I･ 6.10

[

6,OO

i 4.00Ii1

5.75

4.25

4.60

4.91

5.67

6.60

7.00

4.38

11l

1

f/

4.70

5.00

Aki".astra,ig'hLL Asphalt

l

i11l

iI

i

l

j

5.0

75

10.0

7.0

(o)

5.7

kro)

2.7

(o)

1.8

(o)

1.0

(o)

O.3

co)

tE

E

g,1 I

i(2.1)l

7.6 II

(1.9) i

15.0

(2,3)

3.o 1/

JCI.2) 1

l1.6 il

(o.6>l

o.5 l

(O.2) ]

11.0

(4.0)

93(3.6)

7.0

f4.3)i

'4o[(2.2}i

12D lCl.O)l

O.7 l

<o.¢I

5,87

6.80

12.5

15.0

20.0

1

1]

1i

l

li'

l

il

11.9

(4.9)

10.1

(4.4)

8D(5.3)

48(3.0)

22l(,iiZ' l･

i(o,5)l

12.6

(5 6)

10.8

C5.1)

83C5.6)

5.6

(3.8)

2.6

(1.6)

O.9

(O.6)

7.13

4.50

i

14.0

(7.0)

12.0

(6.3)

8.4

(5.7)

6.6

C4.8b

3rO

C2.0)

1.0

<O.7)

:

l-'I1

Es

i

-l

l

1

II l

I

1

ll

l li

I

II I

1 30

1.33

l 85

1.67

1.60

1.67

I157I 1.70 -I

1.63

2.59 j,.2, I

2.00

2.33

l 1.80

1.771

1

2.g6 l

2.67

1.89

3.07

3.11

l2.20 il 2.60

I I2.67 2.99

:;i

I

/

ti

!

2.00

2.ao

3.11

3.67

3.00

3.33

1

l

l

I-i

l-1

!i

I･ -

!

1-1

l

l･ ww

l

( ) shows the weight ]nerease.

crtcpe

pa

sa-'

dioua

euao=di"pt

ouaCT-ge

cr

=---ditc

ohcup'gBB'

:mKM'.c'･

8u:

esoe℃ge

<o-

5･orr

e

en

oo

600 Chuzo lTAKURA and Teruo SuGAwARA

Figs. 42 and 43 show the relation of bulk specific gifavity, variation

of weight, void ratio and asphalt conten't of mixtures.

,

TRINIDAD ASPHALTz,oo tz -

WEIGHT INCREASS

x 1.H.1

-as4gabM j17eTEH

FREEZING50CYCLESOF

ANI)anIAWING'

lsTEIGHT !NCREASE'

,

t,7S J,Js AFt'ER LDAysIrrft4ERsloN'

EULKS .ECIFIC-GRAVITYx mal th--,

lx VOTD RATIO

1.

l,se i,ie 4e.×- A=B==

BUI,KSPECrPICGRVARIATrONOFWEIN

.

c--･ VelDRATIO

N.

Ll)t tas le

Nx L

..,:,,

L,Xttt-tt.tt-ttt

tao- l, o

B A co lozo 30 4050 6e7o eo o leo

-2.0 l,2

1"EIGH･r IN

-- AFII'ER 5oFREEZING

WErc,F'v IN-- rv AlffER u D-l,75. li5･･

N/ ×

S'm--- HULK spticN･

r

wh VOID RATIA

.

1tso LIO 40

A=BVLK SPE, B ±=VARIATIO

c =vorD RAT-x

'

:'1,l5 -tes 20

.

×x '

e ts

:" ,

zua /,oo -0

o A co /ole 30 40 seGo 7eoa 90 iQS

wgeaxITY

Fig. 4Z Relation of Bulk specifif gravity, variation

of weight, void ratio and asphalt eontent.

sTRM'Gitr' AgPHAI,T

INCRASE CYCbES OF ANI) THAWING INCHEASE DAYS IvaIL,:R:･ION

GRAV!TY

SPECIFIC

opGRAVITr

WE:GHT

Fig. 43 Relation of bull< specifie gravity, variation

of weight, void ratio and asphale content.

2. Variation of toughness.

The toughness of bituminous mixture wa$ affected by freezingand thawing actions. As shown in the Figs. 40 and 41, from thesetests some interesting results were obtained, for example, the repeti-

tion of freezing and thawing resulted in some increase, o£ toughness

within 10 to 20 cycles, This £act led to the eonsideration that thisaction might cause some settlement in 'the eonstitution of 'the mixtuires,

And in spite o.E the fact that some kinds o.E non-absorptive speeimens

contained 50 and IOO% o£ bituminous cement, their toughness was

DynamicTestsontheStabilityofBituminousMixturesforPavement 601

redueed, when they were subjected to repetition of freezing andthawing over 10 to 20 cyeles.- As a result of this test, the toughness

of mixture was considered to be reduced by the repetition of freezing

and thawing.

Chapter 5 A sonic method of studying the temperature sensitivity and stability of bituminous mixtures.

1. General･

Several conventional methods have been used for studying of tem-perature sensitivity or stability of paving materials. Generally, those

methods are .subjected to considerable dirncujties as mentioned in the

preeeding chapters. It has beeome clear that the sonic method is mostsuitable for studying the interior behaviour of cement concrete andother materials. The sonic method may alsobe satisfaetorily used fordetermination of stability of bituminous mixtures just as of concrete,

and many of the diMeulties mentioned may be eliminated. Accordinglythe sonic apparatus was applied to bituminous mixtures, and was used

for the purpose of cheeking compatibility and ability of experimenton stability of bituminous mixtures.

2･ Sonic apparatus (photograph-3).c;,+7),s),fo,in)

The constitution of this equipment is sehematically shown in Fig.

44. The driving unit consists of variable audio-oscillator, an amplifier

and a driver. The oseillator, so-ealled "Audio frequency oscillator

.･

iSxs.- ,tT.･-tl････,/1/l･k"//i',･ge, .,･

IliSllli

''' ee'`'

t/L,i,i,1its･-･･

g

ge･-}･････-

Photograph 3

Sonic apparratus.

602 Chuzo ITAKURA and Teruo ･SuGAWARA

DRIVING CIRCUI[T

OSCI!,LATOR

l

----------J11

AMPZ!EIER

[rr

Ii

Il

[L

mp--L----------"

OSCILLOSCOPE (NOTE)

ME[IllI]R

-;1

ll

II

AMPLIFIER

DRIV!NGUNIT .

'

SPECIP'I'EN

PICK rJP

PICK UP CrRCUIT

Fig. 44 Schematic diagram of a sonie device.

Model RC-2K (made by the Matsushita EIectrie Industrial Co. Ltd,)

has three frequeney ranges o£ 20-200, 200-2,OOO, 2,OOO-20,OOO cycles persecond; the accuracy of this oseillator is within 1% of frequency.

The pick-up circuit consists of a Roehelle salt crystal pick-up(produeed by Nihon Denshi Sokki Co. Ltd), an amplifier and indicator,

The indieator consists of micrometer and cathode-ray oscilloscope so-

eallect "A National CT-75 Cathode Ray Oscilloscope" (produced by theMatsushit'a Eleetric Ihdustrial Co. Ltd.).

The dynamic modulus ef elastieity was obtained on three 6 by 6

by 25cm bars of eaeh sort of composition. The eoarse aggregateswere well-graded crushed stones and the fine aggregates devided into

two gradings, were crushed quartz sand. The cement used as mineral

fi11er, amounted to five percent by weight o£ total amount o£ thematerial; the compositiQn of mixtures is shown in Table-6. Photo-graph-4 shows the molding devices. The molding form was made ofwrought iron, because the form made of cast iron of the same size

broke upon application of tamping pressure o£ 200 kg per sq.em (about3,OOO psi). From this accident it was realized that the propagation of

pressure in hot bituminous m2xtures is approximately the same as in

Dynamic Tegts on the Stability of Bituminous Mixtures for Pavement 603

;./ .sT-r･'.･--.,･1"('lrt.･,,.s''tt.'lctts-l･tglt.'.if-."'..',.r:,:k".-..de,/'l""'='l"'-i,-iXk'.t･･'.nf.al..

Photograph 4

Molding device.

TABLE 6 Compositions of mixture (dy weight)

Kind

AsphaltMortar

Asphaltcontent c%)

i

/

Topeka

7.5

9.0

10.5

12.0

7.5

9.0

10.5

12.0

Filler

(%)

Crushed stone c%)

MMi30-20

mml2o-ls 1 mm15-10

MMi10-5 i

5

5

5

5

5

5

5

5

-1 mm5-O

2.17

2.13

2.09

2.06

Sand (.e.')

1

1

L

120.21

19.85

19.49

19.19

mm1.2-O 6

43.75

43.00

42.25

41.30

24.05

23.65

23.25

22.85

/

:

1

7.5

9.0

10.5

12.0

5

5

5

5

23.17

22.75

22.34

21.95

11.58

11.38

11.17

10.97

17.02

16,72

16.41

16.16

AsphaltConerete

/

1

1

4.65

4.57

4.48

4.40

l

/

mm6,3-O.15

43.75

43.00

42.25

4L30

24.05

23.65

23.25

22.85

1

24.05

23.65

23.25

22.851

24.05

23.65

23.25

22.85

liquid substances, so that the final molding device was designed with-

regard to Pascal's law.

Brittle bituminous mixture was changed to liquid state by app]iea-

tion of high pressure, and this phenomenon might oceur originally in

heat exchange of bituminous eement. Then it was suggested thatthe mixtures might be completely compacted by application of a suitable

compacting machine, if obtainable even in low temperature.' The pres-

sure applied in making specimens was 210 kg per sq.cm.

604 Chuzo lTAKuRA and Teruo SuGAwARA

3. Determination of dynamic medulus of elasticity.

The dynamic modulus of elastieity is ealculated from the funda-mental tra,nsverse frequency, weight and dimensions of test specimensby the following equation:

E.. 41 wf.,

,s whexe ･ E: dynamic modulus of elasticity in kg per sq.em VV: weight of speeimen in g.rams l: length of speeimen in em S: eross seetional area of test speeimen in sq.em

f: frequeney in cyele per second

Tables-7, 8, and 9 show the relation between the bituminous content

in mixtures and the dynamic modulus o£ elasticity of them obtainedby this sonic apparatus. Figs.-45, 46, and 47, show the relation between

the bulk specific gravity and dynamic modulus of elasticity of the

s,ame mixtures at various temperatures, ,

TABi.E 7 Dynamie moelulus of elastlcity of bituminous m6rtar

Asphaltcontgnt

(%)

7.5

I･No. i

Dynamic .modulus of elasticlty (kglcm2)

1 2 3avev.

. Io09

22!,OOO

205,OOO

205,OOO

210,300

oocll 2oec

li

132,OOO

149,OOO

148,OOO

143,OOO

1I

129,OOO

126,OOO

123,OOO

126,OOO

9.0

Ill:1 avec.

I

217,000

199,OOQ

230,OOO

215,300

166,OOO

154,OOO

181,OOO

167,eoo

iII

1

1

126,OOO

125?OOO

158,OOO

136,300

10.5

i

12,O

1 2 3aveT.

ii[1

Ii1

199,OOO

lg6,oeo

2o4,ooe

199,700

178,OOO

177,OOO

177,OOO

･ 177,300

; 154,OOO

156,OOO

131,eoo

147,OOO

I

1 2 3aver.

187,OOO

169,OOO

159,OOO

171,700

'

l

l

12s,oeo

124,OOO

126,OOO

125,OOO

i

li

122,OOO

119,OOO

126,OOO

122,300

Dynamie Tests

TABI.E 8

on the Stability pf Bituminous Mixtuves

Dynamic modulus of elasticity

for

of

Pavement

Topeka

605

Dynamicmodulusofelastieity(kglcm2)Asphaltcontent

(%)

No.'-loOc ooc 200C

7.5

ll

;i

l

i

1 d 3aver.

290,OOO

294,OOO

270,OOO

284,700

206,OOO

211,OOO

257,OOO

224,700

199,OOO

212,OOO

239,OOO

216,700

9.0

10.5

1 2 3aver.

!263,OOO I2s3,ooo I26s,ooo .I

261,300

257,OOO

231,OOO

198,OOO

228,700

202,OOO

199,OOO

194,OOO

198,300

lE

1 2 3aver.

292,OOO

292,OOO

256,OOO

280,OOO

l

i1

12.0

1 2 3aver.

250,OOO

270,OOO

251,OOO

257,OOO

214,OOO

255,OOO

201,OOO

223,300

212,OOO

244,OOO

202,OOO

219,300

187,OOO

193,OOO

193,OOO

191,OOO

172,OOO

191,OOO

171,OOO

178,OOO

3

t- rv g Y sdi

mo-

52

."

.r)

va 6 ℃

: u' X.'

eo tl kT tt ' .h.

o''1'Bl'

E.' 'O'

."-tttttlI,' e,' g'.sz･

'

tttt-ttt'

t. tt.-lt,,, +-,.. pt---

---r-

--t1ttt-tt-tttt--

･'-'･･''744.4, ..,

---1+.-t-+-t''''',eL.ny.

,.- ---pt--,..b""':-･-''

t ol,･'･･,･o,･ --+-

--t------4.,o･.･･ .;;..pt.

･･ ..M'"r-O''"..-･ o･･

ei･Qilet,....

----T--,---ti-t'

-v

g･9b 2.

Fig, 4g

10

Relation

modulus

2.a5 $,20 2.26･ Bulx spea! fSc gtiavitY

between bulk specifie gravity and dynamie

,of e!asticity at test tempevature 20℃.

g,aQ

606 ' ChUzolTAKuRA 'and [Ireruo SuGAwARA '

[I]ABI,E 9 Dynamic modulus of elasticity of asphalt eoncrete

Asphaltcontent

c%)

7.5

9,O

10.5

No.

1 2 3aver.

1 2 3aver.

1 2 3aver.

12.0

l,I- 2i

i3 aver.

Dynamic modulus of elastieity (kg/eme)

-100C

281,OOO

230,OOO

251,OOO

254,OOO

271,OOO

233,OOO

272,OOO

258,700

294,OOO

283,OOO

288,500

oec

192,OOO

176,OOO

179,OOO

182,300

237,OOO

200,OOO

192,OOO

209,700

196,OOO

194,OOO

195,OOO

280,OOO

280,OOO

247,OOO

269,OOO

iI

l

180,OOO

188,OOO

180,OOO

182,700

200C

179,OOO

162,OOO

174,OOO

!71,700

197,OOO

194,OOO

Z69,OOO

186,700

177,ooe

170,OOO

173,500

197,OOO

192,OOO

178,OOO

189,OOO

3

ktu F,

×va

,.x

O-., 2

LJ.

3 v,

f'

k'xg.-･

th £.I j P, e u t'i

E: a

oott 1..

'･',o'

tttt ･' ･'

--

''tttt

tttt't-tttttttt.1tt t.. ttt.tt

t.

tlttttt tt..'･'' o･,･tt-t tt tt'eo

tttt-tt'ttt,,,o'

2 05

'Fig,

2,10 2,15 2.L,O 2,26 fiul,k apet.i S.eS,-- Epavlty

46 Relation bet"Tben bulk specific"gravity and dynamic

modulus of e!astieity at test temperature O"C,

'

2.30

'

3

-Nex"

.ko

in.H2x

.X

C:P.

r.

℃

zz1ges

a:-"'h

Q

Dynamic Tests on the Stability. of Biturninous Mixtures for Pavement 607

'

,

,,o"'-tt,:o:･8･','O,.:o･i,:'

-t---lt -o.･O'.-

.･･' 1'

--et tLt-.tt

-4tt---t''-lo･:O.e:'ttt

i--t

------ .- 't'.--tt

,','','

:;"･;,p'r'e･L"-

･' ;2-･･ije.e･ny 8

-t-t--!--t-:-t-----f-.i,,',,'.-O't---.----t--

.,,･ .. .`,. ,'' ;pt.:.d."E-r'

L..s't..-,ly,Tf;.s`F,.'

:.''.'"2.J'if.･,..,--,

--

"

.05 2.XO2.15 R,20 2,252,8 BuIk, speciC1c gvavtty Fig. 47 Relation between bulk specific gravity and dynamic modulus of elasticity at test temperature -100C.

' ' ' 4. Conclusions.

The method and apparatus descri.bed are believed by the presentauthors to be suitable for the ctetermination of temp. erature sensibivity

or stability of bituminous mixtures. As the results of these prelimi-

nary experiments, the follovgring conelusions were reached.

a) The dynamic modulus of elasticity of variousbituminous mix-tures is affeeted by temperature and composition.

b> It was considered to be certain that eonstant relationship exists

between stabiliey and temperature, and bulk speeific gravity anddynamic modulus. Aceordingly the temperature sensitivity andstability of bituminous mixtuTes may be determined accurately andsatisfactorily by the sonic apparatus.

e) The dynamic moduls of elasticity of the bituminous mixture

of three kinds were 1,2 to 1.7×105kg per sq.cm in asphalt mortar,1.8 to 2,6×105 kg per sq.cm in Topel<a and 1,7 to 2.0×105kg per Sq.cmin asphalt concrete h} normal temperature respectively,

d) As shown ,in .fiiiguxes, these resuits formed bands 92% of the

measurect values at 2e"C, 87% at -iO"C aiid. 80% at ODC were imeluded

respeetively and the width of the bands was O.5×105kg per sq.em;while their upper and ]ower Iimits were shown by the equations:

608 Chuzo l'rAKuRA and Terue SUGAWARA

at --100C upper.limit Y=(4.00X-6.20)×105 lower limit Y= (4.00X-6.70)×105

at OOCupperlimitY=(3.20X--4,95)×105 lower Iimit Y== (3,20X-5.45)×105

at 200C upperlimit Y=-(4.80X-8.44)×105 lower limit Y= (4.80X-8.94)×105

where Y:dynamicmodulusofelasticityinkgpersq.cm, X: bulk specific gravity of a speeimen.

But i£ the width of the bands was redueed to O.4×105 kg per sq.cmas shown by dotted lines inside the band shown in the Figures, the

percentage of values £alling within the bands would be reduced to82% at 200C and 81% at -100C. e) The authors are planning to eontinue the stability measure-ments with greater aecuracy by the preparing more suitable speei-

mens in respect to size and by providing a device capable o£ controHingthe temperature variation of speeimens and testing apparatuses.

Chapter 6 Static test by Hubbard stability test apparatus.

A Hubbard stability test apparatus of 6 inch inner diameter wasused to make tests on temperatu:e sensitivity of both kinds of bitumi-

nous mixtures o£ bituininous concrete and of bituminous mortar. Inthese tests the Akita straight asphalt was used. In studies of bitumi-

nous conerete £eur kinds of mixture 7.5%, 10%, 12.5% and 15% o£asphalt eement colttent with mineral fi11er were tested. In bituminous

mortar using three gradings of sand in proportion 1 (O.15 to O.3mm)to 1 (O.5 to !mm) to 1 (1 to 2mm) by weight, five l<inds of mixture

were tested 5%, 7,5%, 10%, 12.5% and 15% of bi'tuminous cement

eontent without mineral fi11er. These sensitivity tests were per£ormedat ---sOC, 50C, 100C, 150C, 200C, 250C and 309C with both types of

mixtures. ' The test results are shown in Figs.-48 and 49. Each line shows the

relation between crushing strength (commonly this value indicates the

stability) and temperature.

On the other hand Tables-･-1,O and 1!1 show the pereen'tages ol]

s'tability of each ld'nd of mixture iii which 10% bituminous eement

eonten't and 150C test temperature used as the base. The resultsobtained from the above may be stated as follows:

Dynamie Tests on ehe StabiLi'ty of Bituminous Miktut'es for Pavement 609

Z5

zo

.. IS

g

ps8Aee

-<.

pt

S 10

9z'1

ki

$gco

5

o -S O S ra IS W "25 oo .lf ua Tft},tpLHAaluR-E, ( ec)

Fig. 48 Relation between stability by Hubbard test

and test temperature on asphak eonerete.

1) The sensitivity of bituminous mixtures measured by a Hubbardstability test apparatus was remarl<ably affeeted by temperature varia-

tion, but there were no considerable differences among the variousspeciinens constituted o.E different qualities of bituminous cement,

I'hese facts might be taken to show that 'ehe sensitivity o£ bituminousmixtures was influenced by the sensitiveness o:ff.the bi'tuminous eemen't

tzsed in mixtures.

'

'

-

s"

.---.e rny

:.k

.

-ori-'

sNm"

'

!L:Ko

'

o

K-s'. t" '

' --- t

.

--

GIO Chuzo ITAKr.Jl<A and [l]eruo SuGAWA'RA

25

･zo

nq/5s /

g-

Y

H,.-

v

p-lOe'tiSHpx

s

'

.JSot'

-' d.IO,-e.O

s.-'e

,

0IS7e

-so s !0 /5ZO Z530 J ,DEMPliRATUBE CeC)

Fig. 49 Relation between stability by Hubbard test

and test temperature on asphalt mortar.

2) The stability of bituminous concrete was affected remarkably

by bituminous content. The stability of mixture of comparat!velylower bituminous content showed' high stability at normal atmospherie･

temperature, while the mixture of either high or low bituminouscontent showed lower stability at low temperatures. The optimumbituminous content as determined by this test wa$ ZO to 12.5%.

Dynamlc Tests on the Stability o£ Bituminous Mixtures foir ?avement 611.

T,yBT,E 10 Percent stability of asphalt concrete of various

compositions at various temperatures.

(Ste.bS'YZY..Oi ,2S.2h.2tt ,C,O.eCg2t,:,Of,g',?.%. ZO,":,e,".t at)

Testtemperature (oC)

-5

510

15

20

25

30

35

Peveent stability

7.5 % 10,O % 12.5 % 15.0 %

324

226

144

66

42

38

38

l

l1I

.I

I

E

416

228

150

100

52

36

30

24

l

i

l

iil

ll

440

220

134

44'

28

18

Ep

ll]

260

152

66

34

22

12

[[tABLE 11 Percent stability of asphalt mortar of

eompositions at various temperature.

(Stability of asphalt mortar of 10% asphalt content at test temperature 150C being taken as 100%

vaicious

)

Testtemperature

(oC)

II

)

Pereent stability

-5 510

15

20

25

30

is.o% 1 7.5 %

E

iiIl

l

1135

585

310-

135'

90

45,

45

I

I

1l

1260

560

250

110

85

25

10,O %

1165

500

250

100

85

35

i 12,5 %!j' 15.0 %

l

E

l,

IF

t

735

460･

235

75

45

35,

I

ll

565

410

70

50

40

25

3) The stability of bituminous mortar was affeeted by low tempera-

tures, but there were no considerable differences at normal tem-

4) The stability of bituminous concrete was higher than that ofbituminous mortar at saine bituminous content and at the same test

temperatuxe.

61,2 Chuzo l'r,AKURA and Terao SuGAwARA

Chapter 7 Summary and conclusions.

Results of the above investigations are summerized as ifollows:

I, Test procedures,

1. At the normal temperatures be'tween 100C to 300C, various testProeedures showed variation of ehayacteristics in asphaltic mixtures,

except in the case of tests employing the p.resent Charpy impacttesting machine. Among the apparatus used, that which gavesatisfactory results was the Page impact testing machine, while 'the

best xesults were obtained with the soniscope. ･ 2. A't temperatures higher than about 350C, as is generally 1<nown,

the mixture was transformed to fiuid state and began to flow, so th.at

there eovld not be found any suitable procedure to test its stability

as solidL ･･ 3. At temperatures lower than 100C, espeeially below 50C, neither

Hubbard stability testing apparatus nor the present Charpy testingmachine eould show dependable iresults. On the other hand, the Izodimpact testing machi'ne gave suMcient ,results; next came the Pageimpact, while the best one was the soniscope.

4. Although various test proeedures other than using the soniscope,

even those considered as suMcient, served for identifieation o£ eharac-teristics in nominal s'tability of asphalt mixtures, they showed simp'ly

the differenees 'or eomparisons and dict not yield any ･meaning from

the view-point of staties or of dyn,amics. / ･ ' 5.,The soniseope could give dynamie elastic moduli and it isconsidered at presen't to be best apparatus for such tests as thosedescribed in this paper. It is the intention to develop the soniseope

£or determination of various characteristics of asphalt mixtures in all'temperature ranges, exeept in fluid /state, especially at low tempera-

tures, aided sometimes by the Page and the Izod impaee testing;naehines.

II. Test results,.

1. Wide differences were £ound in impaet resistanee, aceordingto the kinds of asphalt used. Asphalt content showing the highestvalue in impaet resistanee was 20 to 25% in every case with the Page

impact testing machine (Figs, 3 to 22), 20% with th,e Charpy and the

Izod (Tables-3 and 4). The, optimum asphalt content for aetual usewas considered as 10 to 15%, under high to low temperatures so far as

'the present qualities of asphalt cement are concerned.

Dyna.tnieTcstsontheStabllityofiBituminoutsZY[ixtuvesforI'avement 613

2. In any eomposition and at temperatures 50'C to 200C, the relation

betvgreen toughness and temperature was quite close to a straight line

on a semi-log. paper (Figs. 23 to 36.).

3. Althdugh there was no remarl<able difference in toughhess or

dynamic stability at temperatu]res below 50C, the abso.lute values were

considerably smaller than those at normal temperature (Figs. 3 to 36).

4･. For the mixtures which have asphalt content of 20% or less,dynamic stability was direetly proportional to aspbalt eontent, the slQpe

of 'the proportion being different aeeording to the mixture compositions

(Figs. 3 to 22).

5. Mixtures in which aggregate of coarser particles were promi-ne･nt, had high dynamie stability (Figs. 48 and 49).

6. It is expected that the dynamic stability of mixtures subjeeted

tofreezingandthawingactionisxatherhigh<Figs.38to41). ,' 7. To get durable asphalt surface course, the improvement ofquality of asphalt eement as we]1 as proper selection of aggregates is

essential.

III. Applicatien of the test results.

I'n field practice, asphalt mixtures eonstituted of rieher than 15%

asphalt inight not be used; aceordingly mixtures of 10 to 15% asphal･t

eontent may be used satisfactorily in actual projects,

As the appHcation of these results, on the test road section of the

National Highway No. 36 between Sapporo City and Chitose Air Port,asphalt mixtures using 12, 13 and 14% of asphalt werb paved, and the

service records wil! be gained thTough next summer (1955).,

IV. Future development of researcla.

Tests on the stability of bituminous mixtures against dynamic

loading in cold elimate should be performed from the view-point o£dynamics rather than from that of statics. The soniscope can be

satisfactorily used £or that purpose. On the other hand, the stability of asphalt mixtuyes against Ioad-

ing depe'nds mainly upon the characteristies of the asphalt cement.The main object in o]rder to get high stability of asphalt cement at

low temperature is to improve the characteristics o£ asphalt cement. Looking toward the production of such a stable asphalt ement,iiivestiga'tions of asphalt mixtures with rubber powder and various

kinds o£ cut back asphalt o£ low viscosity are now being carried onby the authors in the laboratory low temperature room and also as

614 , Ch,uzo l'rAI<vRA and Teruo SuGAWARA

a project of National Highway No. 36 in cooperation with the Hokl<aido

Development Bureau., Regarding the.E"manner of testing the stability of test procedures

on stability of asphalt surface eourse and coating, espeeially against

scaling and ravelliBg due to beating eflieet of tire chaines of high speed

traMc, the use of sand blasting and special ravelling testing machine

in low temperature room is being eonsidered. The latter has beendesig･ned already and is now under trial construetion. The test results

in laboratory will be read.y for publicatioh in the autumn this year.

Acl{nowledgement

These investigations were carried out in the Highway Engineering

Reseach Laboratory, Hokkaido University, Sapporo, Hokkaido, Japan. The authors wish to express their appreciation to Mr. H, C, Ross,Assist. Direetor of･ Researeh, McPhar. Engineering Co. of Canada Ltd.,

and Dr, K, B. Woods, Director, Joint Highway Researeh Projeet, ?uxdue

University, for kind advices on using and composing the current soni-

seope. And they also wish to acknowledge their indebtedness to J.R,Leslie, W. J. Cheesman, L. John Minnick, W.F. Meyers, J. Ph.. Pfeiffer,

J. T. Pauls, E. A. Whitehurst, H. W, Slotboom, and R.N.J, Sall, for their.

helpful research reports.

Finally the appreeiation is expressed to E. Sumitomo, M. Seto,T, Takamori, Kazunori Tal<acla, Y. Horiuchi, T.,Kaku, T. IKamiyama,

M. Kimura, Y. Fujita, Kazuo Takada and T. Arakawa, £or their helpful,and earnest assistance during these investigations.

1)

2)

3)

4)

5)

6)

7)

References

J. Ph. Pfeiffer and ?. M. Van Doorma!: Journal,Institute petroleum Technologist

1936, 22, 414.

J, Ph. ?feifrer and P. M. van Doormal: `℃lassifying by Means of Penetraeion Index."

ReprintfromNationalPetroleumNews. RefiningTeehnology. Feb.1938.J.E. Meyers: "Methodofdetermining toughness of Bituminous Mateeials." En-

gineering News Record, Vol. 67, No. 3, Jan. 18, i913,

R.N.J. Sall: "The properties of asphaltic bitumen", pp, 68. London, 1950.

H. W. Slotboom: "The properties of asphaltie bitumen," pp. 270. L,ondon, 1950.

E. A. Whitehurst: "Use of the Soniscope for Measur}ng Setting Time of Con-

crete", Reprint from ･Proeeedings o£ the A.S.T.M. Vo!. 5J, 1951.E. A. Whitehurst: "The Soniscope-a ll)evice for Field Testlng of Concrete" En-

gineering Reprint, Purdue University. 1951.

8)

9)

10)

a>

b)

c)

1)ynamic'1]estsonthe,StabilityoffBitumin,ousMixturesforPa,vement 615

J. R. Leslie: "Pulse teehniques applied to dynamic testing" Reprint from Peoee-

edings of the A. S. T. M., Vol. 50. 1950.

L Jone Minnick, W. F. MeYers: "Properties of Lime-F!yash-Soil Compositions

Employed in Road Construction" Bulletin 69, Highway Researeh Board,

Washington, D. C. 1953.

J. R. Leslie and W. J. Cheesman: An Ultrasonic Method of Studying Deteriora-

tion and Craeking in Conerete Structures" Journal o£ the American Con-

erete lns'titute Vol. 12, No. 1, Sep. 1949. ･

General References

W. O'B. Hillman: "Bending tests on bituminous mixtures". ?ublie Roads, Vol.

21, No. 4, June 1940. -R, H. Lewis and 3. Y. Welborn: "The physieal and chemical properties of petoleum

asphalt of the 50-60 and 85-10e penetration grades" Publie Roads, Vol. 21,

No. 1, 1940.

J. T. Pauls: "Utility of the immersion-eompression test in studies of bituminous

paving mixtures", ?roceedings Convention Group Meeting, Papers and

Discussions, 1950.

.