This article was downloaded by: [Pennsylvania State University]On: 12 August 2014, At: 06:35Publisher: Taylor & FrancisInforma Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,37-41 Mortimer Street, London W1T 3JH, UK

International Journal of Pavement EngineeringPublication details, including instructions for authors and subscription information:http://www.tandfonline.com/loi/gpav20

Laboratory evaluation of recycled waste concrete intoasphalt mixturesM. Arabani a , F. Moghadas Nejad b & A.R. Azarhoosh aa Department of Civil Engineering , University of Guilan , P.O. Box 3756, Rasht , Iranb Department of Civil & Environmental Engineering , Amirkabir University of Technology ,Tehran , 15875 , IranPublished online: 29 Nov 2012.

To cite this article: M. Arabani , F. Moghadas Nejad & A.R. Azarhoosh (2013) Laboratory evaluation of recycledwaste concrete into asphalt mixtures, International Journal of Pavement Engineering, 14:6, 531-539, DOI:10.1080/10298436.2012.747685

To link to this article: http://dx.doi.org/10.1080/10298436.2012.747685

PLEASE SCROLL DOWN FOR ARTICLE

Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) containedin the publications on our platform. However, Taylor & Francis, our agents, and our licensors make norepresentations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of theContent. Any opinions and views expressed in this publication are the opinions and views of the authors, andare not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon andshould be independently verified with primary sources of information. Taylor and Francis shall not be liable forany losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoeveror howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use ofthe Content.

This article may be used for research, teaching, and private study purposes. Any substantial or systematicreproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in anyform to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://www.tandfonline.com/page/terms-and-conditions

Laboratory evaluation of recycled waste concrete into asphalt mixtures

M. Arabania1, F. Moghadas Nejadb2 and A.R. Azarhoosha*

aDepartment of Civil Engineering, University of Guilan, P.O. Box 3756, Rasht, Iran; bDepartment of Civil & Environmental Engineering,Amirkabir University of Technology, Tehran 15875, Iran

(Received 7 April 2012; final version received 5 November 2012)

Asphalt paving materials are composed of over 95% aggregate by weight. Therefore, the highway engineering andconstruction industries annually consume large amounts of aggregate, usually obtained from natural sources. The increaseddemand for natural stone mining has caused the destruction of natural lands and environmental concerns. This study focusedon the determination of the engineering characteristics of hot mix asphalt concrete using dacite and recycled concrete asaggregates. Formulations were tested using recycled concrete aggregate (RCA) as a partial or total replacement for dacite,including replacement of coarse aggregate (CA), fine aggregate (FA) and filler. The results showed that the optimumformulation was a mixture of dacite CA and RCA FA. The optimal mix was superior to the other tested mixes in all theevaluated properties, i.e. Marshall Stability, fatigue, permanent deformation and resilient modulus.

Keywords: dacite; recycled concrete aggregates; fatigue; resilient modulus; permanent deformation

1. Introduction

In recent decades, growth in the mining industry and the

increased consumption ofminedmaterials have led to a rapid

reduction in available natural resources.Conversely, the high

volume of resource extraction has produced a significant

amount of waste material, with additional environmentally

destructive effects. In consideration of these important

issues, many countries and international establishments have

been working on new regulations to minimise and reuse

wastes (Akbulut andGurer 2007). Asmuch as 12,500 tons of

virgin aggregate are consumed per kilometre of pavement

construction (Zoorob and Suparma 2000), and the reuse of

waste material instead of fresh aggregate in pavement could

simultaneously reduce the demands for aggregate production

and landfill space (Huang et al. 2007).

Construction debris resulting from construction and

demolition (C&D) work constitutes a large proportion of

solid waste. Among the various types of construction

materials, concrete was found to be the most significant

component, comprising approximately 75%, 70%, 40%

and 70%collected from construction sites, demolition sites,

general civil work and renovation work, respectively (see

Table 1 and Li 2002). The use of recycled concrete in civil

works due to shortages of natural aggregate and landfill

sites has been common in Europe and countries such as

Japan and Australia for more than 20 years. The recycled

concrete aggregates (RCAs) used in this study were

prepared from rubble collected from the demolition of run-

down buildings, which cannot be directly used in asphalt

mixtures. Aggregates prepared from primary demolition

had large dimensions; consequently, after transferring to

the laboratory they were crushed (the jaw and hammer

crushers were used, respectively) to form aggregates with

dimensions smaller than 19mm. Note that RCAs have

different physical, chemical and mechanical properties

compared with natural aggregates due to the cement paste

that is attached to the surface of the recycled aggregates.

This cement paste causes RCAs to have a lower density,

greater water absorption and a lower abrasion resistance

(Paranavithana andMohajerani 2006). The use of RCA can

offer the following benefits: (1) economical (reduces the

primary production costs and the cost of waste storage), (2)

environmental (conserves natural aggregate and reduces

landfill use, transport impacts and waste emissions) and (3)

the increased efficiency of asphalt mixes.

This study aimed to evaluate the influence of RCA on

the engineering properties of asphalt concretemixtures. For

this purpose, Marshall Stability, indirect tensile-stiffness

modulus (ITSM), permanent deformation and fatigue

testing were performed on five different asphalt mixtures.

2. Literature review

To date, few studies concerning the use of C&D waste,

especially waste concrete as replacement aggregate in

pavement layers and concrete, have been conducted.

2.1 RCA in new concrete mixtures

In a study conducted by Valeria (2010), an investigation on

mechanical behaviour and elastic properties of RCA is

presented. Several concrete mixtures were prepared by

q 2013 Taylor & Francis

*Corresponding author. Email: azarhooshali@yahoo.com

International Journal of Pavement Engineering, 2013

Vol. 14, No. 6, 531–539, http://dx.doi.org/10.1080/10298436.2012.747685

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

using only virgin aggregates (as reference), 30% finer

coarse recycled aggregate replacing fine gravel and 30%

coarse recycled aggregate replacing gravel. The obtained

results showed that structural concrete up to C32/40

strength class can bemanufactured by replacing 30%virgin

aggregate with RCA. Moreover, a correlation between

elastic modulus and compressive strength of recycled-

aggregate concrete was found andwas comparedwith those

reported in the literature. Finally, on the basis of drying

shrinkage results, particularly if finer coarse RCA is added

to themixture, lower strains could be detected especially for

earlier curing time.

In a study by Kou and Poon (2009), it was found that the

fresh and hardened properties of self-compacting concrete

(SCC) using RCA as both coarse aggregate (CA) and fine

aggregate (FA) were evaluated. Three series of SCC

mixtures were prepared with 100% coarse recycled

aggregates, and the different levels of fine recycled

aggregates were used to replace river sand. The SCC

mixtures were preparedwith 0%, 25%, 50%, 75% and 100%

fine recycled aggregates in Series I and II. The SCCmixtures

in Series III were prepared with 100% RCAs (both coarse

and fine). Different tests covering fresh, hardened and

durability properties of these SCC mixtures were executed.

The results indicate that the properties of the SCCs made

from river sand and crushed fine recycled aggregates showed

only slight differences. The feasibility of utilising fine and

coarse recycled aggregates with rejected fly ash and Class F

fly ash for SCC has been demonstrated.

2.2 RCA in pavement layers

2.2.1 Base and sub-base

The test results reported by Poon and Chan (2006)

indicated that the use of 100% RCA increased the

optimum moisture content and decreased the maximum

dry density of the sub-base materials compared with the

natural sub-base materials. The California bearing ratio

(CBR) values (unsoaked and soaked) of the sub-base

materials prepared with 100% RCA were lower than those

of natural sub-base materials. Nevertheless, the soaked

CBR values for the recycled sub-base were greater than

30%, which is the minimum strength requirement in Hong

Kong.

Using the same methods, Khaled and Krizek (1996)

found that RCA can be used as a base course in highway

pavements if the RCA is stabilised with as little as 4%

cement and 4% fly ash by dry weight of the mix.

Unfortunately, using RCA for base and sub-base materials

is potentially associated with the complications related to

the high water solubility of RCA components, thus causing

an increase in pH in the nearby groundwater systems and

possibly affecting the vegetation within the vicinity of the

roads (Gilpin et al. 2004).

2.2.2 Asphalt mixtures

In a study by Paranavithana and Mohajerani (2006), it was

found that all the volumetric properties (except the

percentage of air voids), the resilient modulus and the

creep values of asphalt specimens containing RCA as CAs

were relatively lower compared with the values found for

similar specimens made with only fresh aggregates.

Also Wong et al. (2007) found that the use of recycled

concrete as fillers/fines can increase the resilient modulus

and reduce the dynamic creep. The resilient modulus test

was performed at two test temperatures (25 and 408C).

At both test temperatures, the addition of RCA increased

the resilient modulus, but a lower increase was obtained at

408C test temperature.

Mill-Beale and You (2010) assessed the use of RCA at

amounts of 25%, 35%, 50% and 75% of the total aggregate

weight in asphalt mixes. The rutting potentials using

asphalt pavement analyzer (APA), dynamic modulus (E*),

tensile strength ratio (TSR) for moisture susceptibility,

indirect tensile test (IDT), resilient modulus and the

construction energy index are determined to evaluate the

field performance suitability, or otherwise, of the mix. All

four hybrid VA-RCA hot mix asphalt (HMA) mixes passed

the minimum rutting specification of 8 mm. The master

curves for the hybrid mixes showed that the dynamic

stiffness of the hybrid mixes was less than that of the

control 4E1 mix, and it decreased when the RCA increased

in the mix. In terms of moisture susceptibility, the TSR

Table 1. Composition of construction waste in South-East New Territories landfills (Li 2002).

Waste type Construction site (%) Demolition site (%) General civil work (%) Renovation work (%)

Metal 4 5 10 5Wood 5 7 0 5Plastic 2 3 0 5Paper 2 2 0 1Concrete 75 70 40 70Rock/rubble 2 1 5 0Sand/soil 5 0 40 0Glass/tile 3 2 0 10Others 2 10 5 4Total 100 100 100 100

M. Arabani et al.532

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

increased with decreasing RCA, with only 75% of RCA

failing to meet the specification criterion in the mix. The

compaction energy index proved that using RCA would

save some amount of compaction energy. Finally, it has

been recommended that a certain amount of RCA in HMA

is acceptable for low-volume roads.

Also Lee et al. (2012) evaluated the pre-coated

recycled concrete aggregate (PCRCA) for HMA. In this

research, slag cement paste used for PCRCA with coating

thickness of 0.25, 0.45 and 0.65 mm to reinforce its ability

is evaluated. The result shows that PCRCA with a coating

thickness of 0.25 mm has the optimum coating paste

volume for HMA mixture. The indirect tensile strength

(ITS) test, moisture sensitivity test and wheel track rutting

test of HMA with substitution ratios of 25%, 50%, 75%

and 100% PCRCA mixture are discussed. The results

indicate that the properties of PCRCA have highly pore

contents, absorption of water and asphalt contents.

However, the physical properties of the PCRCA used as

aggregate and the test of HMA with PCRCA are within the

range of the specification requirements.

3. Experimental methods

In this study, the experimental work was divided into four

phases. Phase I included the collection and characteris-

ation of asphalt binder and dacite and RCA. A 60–70

penetration asphalt binder was used. To characterise the

properties of the base asphalt binder, conventional test

methods, such as the penetration test, the softening point

test and a ductility test, were performed. The engineering

properties of the asphalt binder are presented in Table 2.

The grading of aggregates used in the study (the middle

limits of the ASTM specifications for dense aggregate

grading) is given in Table 3. The nominal size of this

grading was 19.0mm. The physical properties of dacite

aggregate and RCA are given in Table 4.

In Phase II, five asphalt concrete mixes were

investigated. The first mix was an asphalt concrete mix

where all the aggregates used were dacite. This mix was

called the control mix.

In the second mix, the dacite CA [materials retained on

sieve #4 (size .4.75mm)] was replaced by RCA. The FA

[materials passing sieve #4 (size,4.75mm) and retained on

sieve #200 (size .0.075mm)] and filler [materials passing

sieve #200 (size ,0.075mm)] dacite were replaced with

RCA in the third and fourth mixes, respectively. In the fifth

mix, all the aggregates used were RCA. The Marshall Mix

design procedure (ASTMD1559) was used to determine the

optimum asphalt contents (OACs) of all the mixes.

TheOACswere selected to produce 4%air voids. At the

obtained OACs, Marshall Stability, flow, voids filled with

asphalt and voids in mineral aggregates were checked. In

Phase III, the effectiveness of using RCAwas judged by the

Marshall Stability, fatigue, permanent deformation and

resilient modulus (ITSM) tests; a Nottingham Testing

Machine was used for this purpose. Depending on the

results obtained from Phase III, Phase IV focused on

selecting the optimal mix.

Table 2. Test results for 60–70 penetration asphalt binder.

Test Standard Result

Penetration (100 g, 5 s, 258C), 0.1mm ASTM D5-73 64Penetration (200 g, 60 s, 48C), 0.1mm ASTM D5-73 23Penetration ratio ASTM D5-73 0.36Ductility (258C, 5 cm/min), cm ASTM D113-79 112Solubility in trichloroethylene (%) ASTM D2042-76Softening point (8C) ASTM D36-76 51Flash point (8C) ASTM D92-78 262Loss on heating (%) ASTM D1754-78 0.75Properties of the TFOT residuePenetration (100 g, 5 s, 258C), 0.1mm ASTM D5-73 60Specific gravity at 258C (g/cm3) ASTM D70-76 1.020Viscosity at 1358C (cSt) ASTM D2170-85 158.5

Table 3. Grading of aggregates used in the study.

Sieve (mm)

Sieve (mm) 19 12.5 4.75 2.36 0.3 0.075

Lower–upper limits 100 90–100 44–74 28–58 5–21 2–10Passing (%) 100 95 59 43 13 6

International Journal of Pavement Engineering 533

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

4. Mix design

The asphalt concrete mixture was produced based on the

Marshall Mix design. HMA specimens in the form of

briquettes of approximately 101.6mm in diameter and 65–

75mm thickness were manufactured using Marshall

hammer compaction (at 75 blows). Two series of Marshall

specimens were fabricated. The first series of specimens

contained various concentrations of binder to determine the

optimal binder content. The second series was produced at

the optimal binder content to evaluate the HMAmechanistic

properties. For each aggregate blend and asphalt binder

content, at least three samples were produced to determine

the reproducibility of the results (ASTM 2000).

5. Results and discussion

The obtained maximum specific gravities,Gmm, and OACs

of the tested mixes are presented in Table 5. As expected,

the Gmm values decreased with increasing RCA content.

The inclusion of RCA in the mixes increased the OAC

values. These results are due to the lower specific gravity

and the higher absorption of RCA compared with the

dacite aggregate.

5.1 Extraction of bitumen from bituminous pavingmixtures test (ASTM D2172)

These test methods cover the quantitative determination of

bitumen in hot-mixed paving mixtures and pavement

samples. Aggregates obtained by these test methods may

be used for sieve analysis using Test Method C117 and

Test Method C136.

The use ofRCAasCA/FA caused changes in particle size

distribution of aggregatemixtures before and aftermixing and

compaction. An extraction test was used to determine these

changes, and a sieve analysis was performed on aggregate

obtained from this test. The results are presented in Table 6.

Considering that the changes in the particle size

distribution of aggregate mixtures are due to the breaking

and crushing of cement mortar, the use of RCA as CA was

expected to be associated with greater changes. The use of

RCA as CA caused an increase in the amount of fine and

filler aggregate insofar as it exceeded the optimal limit,

causing an excess of fines and filler and a shortage of CA,

with undesirable effects on the engineering characteristics

of asphalt mixtures.

5.2 Marshall Stability test results (ASTM D1559)

The objectives of the Marshall test were to evaluate the

effect of RCA on Marshall Stability and to find the

optimum RCA content. Three samples from each mix

were placed in a water bath at 608C. After 30min of

immersion, the samples were tested for Marshall Stability.

The results for the tested samples are presented in Table 7.

The ‘CA:dacite þ FA:RCA’ samples had the highest

Marshall Stability values after 30min of immersion in the

water bath. Because RCA differs from fresh aggregate due

to the remaining cement paste attached to the surfaces after

the recycling process, this increase in the stability of

mixtures may be explained by a reduced curing time, as

previous studies (Terrel and Wang 1971, Schmidt et al.

1973, Head 1974) have indicated that Portland cement can

reduce the breaking time of bituminous emulsions.

5.3 Permanent deformation test

The tests generally used to assess the resistance of

bituminous mixes to permanent deformation are the

Table 4. Physical properties of aggregates.

Test Standard Dacite RCA Specification limit

Specific gravity (coarse aggregate) ASTM C127Bulk 2.650 2.457 –SSD 2.662 2.471 –Apparent 2.685 2.484 –Specific gravity (fine aggregate) ASTM C128Bulk 2.657 2.463 –SSD 2.660 2.477 –Apparent 2.681 2.496 –Specific gravity (filler) ASTM D854 2.652 2.461 –Los Angeles abrasion (%) ASTM C131 22.60 35.50 maximum 45Flat and elongated particles (%) ASTM D4791 5.00 9.30 maximum 10FA angularity ASTM C1252 55.20 70.10 minimum 40

Table 5. Maximum specific gravity and OAC of the testedmixes.

Aggregate typeMaximum specific

gravity, Gmm OAC (%)

Control:0% RCA 2.648 5.1FA:RCA þ CA:dacite 2.527 5.6FA:dacite þ CA:RCA 2.433 6.5FA&CA:dacite þ filler:RCA 2.621 5.1100% RCA 2.326 7

M. Arabani et al.534

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

Marshall test, the static creep test, the dynamic creep test

and the wheel tracking test (Verstraten 1994). In this study,

the resistance to permanent deformation of RCA mixtures

was evaluated by using static creep test and the dynamic

creep test.

For the static creep test, the creep deformation of a

cylindrical specimen under a uniaxial static load is

measured as a function of time. Deformation values were

measured over time with a linear variable differential

transducer (LVDT). For the static creep test, cylindrical

specimens of 70mm £ 101mm (thickness £ diameter)

were prepared. The test was performed for all mixtures at

the optimal dosage of asphalt binder. Because the risk of

permanent deformation was greater, the heavy-load and

high-temperature test parameters were selected, i.e. the

uniaxial load was 425 kPa (0.4MPa), the temperature was

408C and the load duration was 3600 s.

The dynamic creep test applies a repeated pulsed

uniaxial stress on an asphalt specimen and measures the

resulting deformations in the same direction using LVDTs.

For the dynamic creep test, cylindrical specimens of

70mm £ 101mm (thickness £ diameter) were prepared.

The dynamic creep test was conducted by applying a

dynamic stress of 100 kPa for 1 h at 408C. The dynamic

creep test was conducted by applying a dynamic stress of

100 kPa for 1 h at 408C. In each test, the sides of the

specimen were capped, and the sample was placed in the

loading machine under a conditioning stress of 10 kPa for

600 s. Next, the conditioning stress was removed, and a

stress of 100 kPa was applied for 2000 cycles, which

included a 1 s loading period and a 1 s resting period.

The values of static creep compliance are shown in

Figure 1. The results of the dynamic creep test are given in

Figure 2, showing permanent deformation versus load

cycles. The results of the static creep tests show that the

samples without RCA had more permanent deformation

than the samples containing RCA as FA or filler; these

additions resulted in reductions of permanent deformation

by 28% and 12%, respectively, compared with the control

samples.

The results of the dynamic creep tests show that the use

of RCA as FA or filler also resulted in reducing permanent

deformation. The use of RCA as FA or filler resulted in

reductions of permanent deformation by 25% and 16%,

respectively.

Both tests showed that the best of RCA placement in

reduction of permanent deformation was the replacement of

the FA. Because RCA ismore angular than dacite aggregate,

this additiongeneratedhigh frictional and abrasion resistance

in the resulting asphalt mixtures. Despite its angularity, the

use of RCA as CA in asphalt mixtures increased permanent

deformation, probably because the relatively weak cement

mortar-coating aggregates decreased abrasion resistance.

5.4 Resilient modulus test, modulus of resilient (ASTMD4123)

In recent years, there has been a change in the philosophy

of asphalt pavement design from a more empirical

approach to a more mechanistic approach based on elastic

theory. Design methods based on elastic theory require

inputs of the elastic properties of pavement materials. The

resilient modulus of asphalt mixtures, measured in the

indirect tensile mode (ASTM D4123), is the most popular

form of stress–strain measurement used to evaluate elastic

properties (Tayfur et al. 2007).

Table 6. Changes in aggregate size after mixing and compaction.

Passing (%)

Sieve (mm) Lower–upper limits Total dacite CA:RCA Changes (%) FA:RCA Changes (%)

19 100 100 100 0 100 012.5 90–100 95 100 5.3 95 04.75 44–74 59 76 28.8 59 02.36 28–58 43 54 25.6 47 9.30.3 5–21 13 23 76.9 15 15.40.075 2–10 6 11 83.3 7 16.7

Table 7. Marshall Stability test results for the tested mixes.

Marshall Stability after 30minimmersion (kN)

Aggregate type Stability Average

Control 16.87 16.9716.6317.4

100% RCA 12.11 12.0511.5612.48

FA:RCA 19.12 19.4619.6919.56

CA:RCA 13.35 12.9712.4913.06

Filler:RCA 17.89 17.7417.6117.72

International Journal of Pavement Engineering 535

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

Three samples for each mix were tested under the

diametrical modulus of resilient (MR) test at two test

temperatures (258C and 408C). Cylindrical specimens of

101.6mm in diameter and 65mm thickness were used in this

test. The resilient modulus of the samples was determined by

the indirect tensile strength method (ITSM) using a

Nottingham Asphalt Testing system. The resilient modulus

test was performed by applying a linear force along the

diameter axis of the specimen. Each loading cycle is 1.0 s

long,while the total durationof loadingandunloading is 0.1 s;

therefore, the rest time period of each cycle is 0.9 s. In the

resilient modulus test using ITSM, the value of the resilient

modulus can be determined from equation (Arabani 2011):

ER ¼pðqþ 0:27Þ

t £ DH; ð1Þ

where ER is the stiffness modulus (MPa), P is the repeated

load (N), q is the Poisson ratio that is assumed to be 0.35 in

HMA, t is the thickness of HMA sample (mm) and DH is the

recoverable horizontal deformation (mm).

Figure 3 shows the average obtained MR values for the

tested mixes. The figure shows that ‘CA:dacite þ

FA:RCA’ had the highest MR values among the tested

mixes. At the lower test temperature of 58C, the resilience

is higher, indicating the stiffest material condition under

the recoverable deformation behavioural conditions. The

resilient modulus decreases with the increase in tempera-

ture with and without RMA asphalt samples, due to the

higher sensitivity of asphalt binder to the temperature

changes, whereby when the temperature increases,

viscosity and resilient modulus of asphalt binder decrease.

This causes increasing slip in the aggregate and softening

of the asphalt mixtures, whereby the resilient modulus of

samples with and without RCA declines. The average

resilient modulus of the control mix at 258C was 932MPa.

This value reached 1345MPa for ‘CA:dacite þ FA:RCA’

Time (S)

0

2000

4000

6000

8000

10000

12000

14000

16000

0 1000 2000 3000 4000

Per

man

ent

stra

in (

µm

/m)

Control 100%RCA FA:RCA CA:RCA Filler:RCA

Figure 1. Time versus deformation in the static creep test.

0

2000

4000

6000

8000

10000

12000

14000

0 500 1000 1500 2000 2500

Cycles

Per

man

ent

stra

in (

µm

/m)

Control 100%RCA FA:RCA CA:RCA Filler:RCA

Figure 2. Number of cycles versus permanent deformation.

M. Arabani et al.536

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

samples, i.e. a 44% increase in the resilient modulus value.

The average resilient modulus at 408C increased from

430MPa for the control mix to 706MPa for ‘CA:dacite þ

FA:RCA’ mixes. This behaviour can be attributed to the

same reasons mentioned above with respect to the

permanent deformation testing.

5.5 Fatigue performance

Fatigue cracking is one of the three major distresses (i.e.

fatigue cracking, low-temperature cracking and rutting) of

flexible pavements. Fatigue cracking is mainly caused by

repeated traffic loading, and it can lead to a significant

reduction in the serviceability of flexible pavements. The

cracking resistance of HMA mixtures is directly related to

the fatigue performance of flexible pavements. Therefore,

the laboratory characterisation of the fatigue behaviour of

HMA mixtures has been a topic of intensive study for

many years (Shu et al. 2008). The fatigue process occurs in

three distinct stages – (1) crack initiation: development of

micro cracks, (2) crack propagation: development of

macro cracks out of micro cracks resulting in stable crack

growth and (3) disintegration: collapse and final failure of

the material due to unstable crack growth (Moghadas

Nejad et al. 2012).

The indirect tensile fatigue test is able to characterise

the fatigue behaviour of the mixture. Fatigue tests were

carried out in both controlled strain mode and controlled

stress mode. In the controlled strain mode, the strain was

maintained by reducing the stress on the sample. In the

controlled stress mode, the stress was held constant to

increase the strain within the sample (Arabani et al. 2010).

The relationship between tensile strain and the number of

cycles to failure for each material was established. A linear

relationship was recorded when strain is plotted against the

numbered cycles to failure in logarithmic scale, and the

fatigue life prediction equations were developed (Mogha-

das Nejad et al. 2010). Using a regression analysis, the

fatigue equations were developed, which are in the form of

Wohler’s fatigue prediction model (Equation (2)):

Nf ¼ k1

1

1t

� �k2

: ð2Þ

where Nf is the number of cycles to failure of the

specimen, 1t is the applied strain and k1 and k2 are the

coefficients related to mixture properties.

The fatigue life of specimens was measured with the

Nottingham Asphalt Tester in the constant stress mode.

The fatigue criterion was considered, creating a vertical

displacement that equals 1mm. Fatigue life is determined

by applying a repeated load with fixed amplitude along the

diametrical axis of a specimen. The repeated load consists

of 0.1 s of loading and 0.4 s of rest in each cycle.

Cylindrical specimens with a diameter of 101.6mm and a

thickness of 40mm at 4% air void were tested at 258C.

According to the local conditions that the most pavement

failures occur at high temperatures, the authors decided to

use this temperature.

Figure 4 shows the results of these tests. In this figure,

regression lines were drawn through the mean results of

each sample at each strain level. The results show an usual

linear relationship between the logarithm of the applied

initial tensile strain and the logarithm of fatigue life.

Analysis of the obtained fatigue results showed a

significant improvement in the fatigue life of

‘CA:dacite þ FA:RCA’ mixes. The use of recycled

concrete as an FA may improve the fatigue life of asphalt

mixtures for two reasons. First, improve the fatigue life of

asphalt mixtures caused changes in the particle size

distribution of aggregate mixtures before and after mixing

and compaction. These changes cause an increase in the

amount of filler, decrease in air void and create a dense-

0

200

400

600

800

1000

1200

1400

1600

Mixtures

Res

ilien

t m

od

ulu

se (

MP

a) 25°C40°C

Control 100%RCA CA:RCA FA:RCA Filler:RCA

Figure 3. Comparison of resilient modulus values at 258C and 408C.

International Journal of Pavement Engineering 537

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

graded structure of aggregates interlocked with each other

in comparison with a control mixture. Second, the addition

of RCA may increase the optimum asphalt binder content,

which has a direct relation to the fatigue life of asphalt

mixtures.

However, the use of RCA as a CA unfortunately poses

a major problem, i.e. it adversely affects the mechanical

properties of the asphalt concrete mixes compared with the

control mix. This behaviour is likely due to the effect of

mixing and compaction of the RCA particles and the

breakage of the relatively weak cement mortar attached to

them. For every type of the mixtures, the fatigue equations

are presented in Table 8.

6. Concluding remarks

This investigation was undertaken to evaluate the

performance of asphalt concrete mixes using different

percentages of RCA and to find the optimal percentages

for the replacement of dacite aggregates with RCA. To

fulfil this objective, laboratory evaluation of asphalt

concrete mixes with different combinations of dacite and

RCA aggregates was conducted. Based on the experimen-

tal results, the following conclusions can be drawn:

(1) The replacement of dacite CA with RCA in the

asphalt concrete mixes was not effective because it

adversely affected the mechanical properties of

the mixes compared with the control mix. This

behaviour was because the effect of mixing and

compaction fractured the RCA particles and broke

the relatively weak cement mortar attached to

them.

(2) The asphalt concrete mix using RCA as FA, with a

dacite CA and dacite filler, was found to be the

optimal mix. But the use of RCA as FA increases

the amount of CaOH which can cause environ-

mental issues.

(3) The results of the Marshall, resilient modulus and

fatigue tests showed that the addition of RCA as

fines and filler aggregate increased the Marshall

Stability, resilient modulus and fatigue life of the

mixtures. This increase was the most pronounced

for the samples with RCA as FA.

(4) The results of the static creep test showed that the

samples without RCA showed more permanent

deformation than the samples containing RCA as

FA or filler. The addition of RCA as FA or filler

resulted in reductions of permanent deformation

by 17% and 6%, respectively, compared with the

control samples.

(5) The results of the dynamic testing showed that the

use of RCA as FA or filler resulted in reductions of

permanent deformation by 25% and 16%,

respectively, compared with the control samples.

100

1000

10000

100000

10 100 1000 10000 100000

Strain (µm/m)

Cyc

les

to f

ailu

re

Control 100%RCA FA:RCA CA:RCA Filler:RCA

Figure 4. Comparison of fatigue behaviour of the different mixes at 258C.

Table 8. Fatigue prediction equations of mixtures.

Mixtures Nf k1 k2 R 2

Control Nf ¼ 2.4 £ 1041 20.62 2.4 £ 104 20.62 0.971100% RCA Nf ¼ 2.5 £ 1041 20.69 2.5 £ 104 20.69 0.972FA:RCA Nf ¼ 1.9 £ 1041 20.46 1.9 £ 104 20.46 0.958CA:RCA Nf ¼ 2.9 £ 1041 20.76 2.9 £ 104 20.76 0.977Filler:RCA Nf ¼ 2.4 £ 1041 20.57 2.4 £ 104 20.57 0.946

M. Arabani et al.538

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4

(6) Both the static creep and dynamic creep tests

showed that addition of RCA as FA or filler can

reduce the permanent deformation of the mixtures.

The best use with respect to reducing permanent

deformation proved to be the replacement of

dacite with RCA as the FA.

Notes

1. Email: m_arbani@yahoo.com2. Email: moghadas@aut.ac.ir

References

Akbulut, H. and Gurer, C., 2007. Use of aggregates producedfrom marble quarry waste in asphalt pavements. Buildingand Environment, 42 (5), 1921–1930.

Arabani, M., 2011. Effect of glass cullet on the improvement ofthe dynamic behaviour of asphalt concrete. Construction andBuilding Materials, 25 (3), 1181–1185.

Arabani, M., Mirabdolazimi, S.M., and Sasani, A.R., 2010. Theeffect of waste tire thread mesh on the dynamic behavior ofasphalt mixtures. Construction and Building Materials, 24(6), 1060–1068.

ASTMD1074, 2000. Annual book of ASTM standards. Road andpaving materials, Vol. 04.03.

Gilpin, R., et al., 2004. Recycling of construction debris asaggregate in the Mid-Atlantic Region, USA. Resources,Conservation and Recycling, 42 (3), 275–294.

Head, R.W., 1974. An informal report of cold mix research usingemulsified asphalt as binder. In: Proceedings of the AAPT,110–131.

Huang, Y.N., Bird, R., and Heidrich, O., 2007. A review of theuse of recycled solid waste materials in asphalt pavements.Resources, Conservation and Recycling, 52 (1), 58–73.

Khaled, R.J. and Krizek, F., 1996. Fiber-reinforced recycledcrushed concrete as a stabilized base course for highwaypavements. Evanston, IL: Northwestern University.

Kou, S.C. and Poon, C.S., 2009. Properties of self-compactingconcrete prepared with coarse and fine recycled concreteaggregates. Cement & Concrete Composites, 31 (9),622–627.

Lee, C.H., Dub, J.C., and Shen, D.H., 2012. Evaluation of pre-coated recycled concrete aggregate for hot mix asphalt.Construction and Building Materials, 28 (1), 66–71.

Li, W., 2002. Composition analysis of construction and demolitionwaste and enhancing waste reduction and recycling inconstruction industry in Hong Kong. Hong Kong: Departmentof Building and Real Estate, The Hong Kong PolytechnicUniversity.

Mills-Beale, J. and You, Z., 2010. The mechanical properties ofasphalt mixtures with recycled concrete aggregates. Con-struction and Building Materials, 24 (3), 230–235.

Moghadas Nejad, F., Aflaki, E., and Mohammadi, M.A., 2010.Fatigue behavior of SMA and HMA mixtures. Constructionand Building Materials, 24 (6), 1158–1165.

Moghadas Nejad, F., et al., 2012. Influence of using nonmaterialto reduce the moisture susceptibility of hot mix asphalt.Construction and Building Materials, 31 (1), 384–388.

Paranavithana, S. and Mohajerani, A., 2006. Effects of recycledconcrete aggregates on properties of asphalt concrete.Resources, Conservation and Recycling, 48 (1), 1–12.

Poon, C.S. and Chan, D., 2006. Feasible use of recycled concreteaggregates and crushed clay brick as unbound road sub-base.Construction and Building Materials, 20 (8), 578–585.

Schmidt, R.J., Santucci, L.E., and Coyne, L.D., 1973.Performance characteristic of Portland cement modifiedasphalt emulsion mixes. In: Proceedings of the AAPT,300–319.

Shu, X., Huang, B., and Vukosavljevic, D., 2008. Laboratoryevaluation of fatigue characteristics of recycled asphaltmixture. Construction and Building Materials, 22 (7),1323–1330.

Tayfur, S., Ozen, H., and Aksoy, A., 2007. Investigation ofrutting performance of asphalt mixtures containing polymermodifiers. Construction and Building Materials, 21 (2),328–337.

Terrel, R.L. and Wang, C.K., 1971. Early curing behavior ofPortland cement modified asphalt emulsion mixtures. In:Proceedings of the AAPT, 110–131.

Valeria, C., 2010. Mechanical and elastic behaviour of concretesmade of recycled-concrete coarse aggregates. Constructionand Building Materials, 24 (9), 1616–1620.

Verstraten, J., 1994. Bituminous materials with a high resistanceto flow rutting. Belgium: PIARC TC8.

Wong, Y.D., Sun, D.D., and Lai, D., 2007. Value-addedutilization of recycled concrete in hot mix asphalt. WasteManagement, 27 (2), 294–301.

Zoorob, S.E. and Suparma, L.B., 2000. Laboratory design andinvestigation of the properties of continuously gradedasphaltic concrete containing recycled plastics aggregatereplacement. Cement & Concrete Composites, 22, 233–242.

International Journal of Pavement Engineering 539

Dow

nloa

ded

by [

Penn

sylv

ania

Sta

te U

nive

rsity

] at

06:

35 1

2 A

ugus

t 201

4