" B-SMA shows the best rutting resistance, followed by BL-SMA and L-SMA comes in last." Aggregate type has no signicant effect on low temperature performance.
, followthree S
r curves of dynamic modulus for three SMA mixtures were constructed and B-SMA shows the highest dynamic modulus, while L-SMA shows the smallest dynamic modulus at each
and reduced noise pollution , SMA has been widely adopted inEurope, Australia, USA, Canada, Japan, and many other countriesworldwide, as a surface course for heavily trafcked roads. Sincethe rst application of SMA in the capital airport highway in1992, it also has been used widely on road surfaces of expresswayin China .
drain-down when this asphalt rubber was used. The results of thewheel tracking tests at 60 C showed that rutting resistance ofARSMA mixtures was better than that of the conventional SMAmixtures. A comprehensive study performed by Ahmadinia et al.[5,6] explored the utilization of waste Polyethylene Terephthalate(PET) in SMA. In this research the waste PET (46% by weight ofthe bitumen content) was added into the mixture in the last partof the mixing process and after adding and blended the binder withthe aggregate instead of mixing the additive with the aggregatebefore adding the binder. The results showed that the addition of
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Construction and Building Materials 41 (2013) 474479
Contents lists available at
evE-mail address: email@example.com (W. Cao).Limestone aggregatePerformance frequency.
2013 Elsevier Ltd. All rights reserved.
Stone matrix (or mastic) asphalt (SMA) is a hot mix asphalt(HMA) consisting of a coarse aggregate skeleton and a high bindercontent mortar. SMA was developed in Germany during the mid-1960s and it has been used in Europe for more than 40 years toprovide better rutting resistance and to resist studied tyre wear. Because of the superior performance of SMA mixture compris-ing its high rut resistance, high skid resistance, high durability, im-proved resistance to reective cracking, better drainage condition
There are many previous researches regarding the modicationof SMAmixtures and the utilization of wastematerials in SMA. Chiuand Lu  investigated the feasibility using asphalt rubber (AR) as abinder for SMA. The results of this study showed that it was notfeasible to produce a suitable SMAmixture using an asphalt rubbermade by blending an AC-20 with 30% coarse ground tire rubber(GTR) with a maximum size of 0.85 mm. However, SMA mixturesmeeting typical volumetric requirements for SMA could be pro-duced using an asphalt rubber containing 20% of a ne GTR witha maximum size of 0.6 mm. No ber was needed to preventBasalt aggregate
Stone matrix asphalt (SMA)
signicant difference in lowSMA mixtures. Also, maste" L-SMA has the best moisture stability" Master curves of dynamic modulus of
a r t i c l e i n f o
Article history:Received 5 September 2012Received in revised form 5 December 2012Accepted 19 December 2012Available online 28 January 2013
Keywords:0950-0618/$ - see front matter 2013 Elsevier Ltd. Ahttp://dx.doi.org/10.1016/j.conbuildmat.2012.12.021ed by BL-SMA and B-SMA comes in last.MA mixtures were constructed.
a b s t r a c t
The main objective of this study was to compare the performance of three kinds of stone matrix asphalt(SMA) mixtures (using basalt coarse and ne aggregates, named B-SMA; limestone coarse and ne aggre-gates, named L-SMA; basalt coarse aggregates and limestone ne aggregates, named BL-SMA). The resultsindicated that B-SMA shows the best rutting resistance, followed by BL-SMA and L-SMA comes in last.However, in terms of low temperature performance of resistance to cracking and moisture susceptibility,they have the reverse sequence. The aggregate type has a signicant effect on rutting resistance, but no
temperature cracking susceptibility or moisture susceptibility was found inComparison of performance of stone matand limestone aggregates
Weidong Cao , Shutang Liu, Zhigang FengSchool of Civil Engineering, Shandong University, No. 17923 Jingshi Road, Jinan, Shando
h i g h l i g h t s
journal homepage: www.elsll rights reserved.x asphalt mixtures using basalt
rovince 250061, PR China
ier .com/locate /conbui ldmat
aggregates. The performance tests including wheel tracking test,low temperature beam bending test, moisture susceptibility test,and dynamic modulus test were carried out on three kinds ofSMA mixtures, which were: (a) both coarse and ne aggregatesare basalt, named B-SMA; (b) both coarse and ne aggregates arelimestone, named L-SMA; (c) coarse aggregates are basalt and neaggregates are limestone, named BL-SMA.
2. Materials and experiments
2.1.1. Aggregates usedCrushed stones of basalt and limestone were used for coarse aggregate and ne
aggregate respectively. In order to reduce test errors, all aggregates were sieved intosingle size particles as per China Standard T0302-2005 . Three particle sizes ofcoarse aggregates (13.216 mm, 9.513.2 mm, and 4.759.5 mm) of two kinds ofstones were chosen. Properties of coarse aggregates as per Chinese specications are shown in Table 1.
Six particle sizes of ne aggregates (2.364.75 mm, 1.182.36 mm, 0.61.18 mm, 0.30.6 mm, 0.150.3 mm, and 0.0750.15 mm) of two kinds of stoneswere used. The basic properties of ne aggregates as per Chinese specications
uilding Materials 41 (2013) 474479 475waste PET into the mixture had a signicant positive effect on theproperties of SMA which could improve the mixtures resistanceagainst permanent deformation (rutting), increase the stiffness ofthe mix, provide lower binder drain down and promotion ofre-use and recycling of waste materials in a more environmentallyand economical way. Furthermore, Baghaee Moghaddam et al. carried out another research on dynamic properties of SMA mix-tures containing waste plastic bottles. The results indicated thatstiffness modulus of mixture increased at lower amount of PETcontent; however, adding higher amount of PET made mixture lessstiff. In addition, PET reinforcedmixtures exhibit signicantly high-er fatigue lives compared to the mixtures without PET. Putman andAmirkhanian  investigated the feasibility of utilizing waste tireand carpet bers in SMA. This study compared the performanceof SMA mixtures containing waste tire and carpet bers (0.3% byweight of total mixture) with mixes made with commonly usedcellulose and other polyester bers produced specically for usein HMA. No signicant difference in permanent deformation ormoisture susceptibility was found in mixtures containing wastebers compared to cellulose or polyester. Also, the tire, carpet,and polyester bers signicantly improved the toughness of themixtures compared to the cellulose bers. Mokhtari andMoghadas Nejad  performed a laboratory investigation on SMAmixtures containing polymers and bers, and then conducteda mechanisticempirical approach to determine the effect ofdifferent additives in increasing the service life of the pavementor reduction of the pavement layers thickness. Their researchindicated that styrenebutadienestyrene (SBS) was more effectivein improving the performance of asphalt mixtures compared tothe bers and the service life of the pavement system modiedwith mineral, cellulose and SBS were 1.07, 1.081 and 1.243 timesmore than unmodied mix, respectively. The research by Xueet al.  focused on a laboratory evaluation of the performanceof SMA used municipal solid waste incinerator (MSWI) ash andbasic oxygen furnace (BOF) slag as aggregates or mineral ller. Acomparison study was carried out to use those solid waste aboveand local materials to design the asphalt mixtures using bothMarshall and SUPERPAVE mixture design procedures. In all theperformed tests SUPERPAVE mixtures proved their superiorityover Marshall mixtures. Tests results showed that nearly 816%of MSWI ash substitution for aggregates and ller is guaranteedto meet the requirement of SMA mixtures. The large amount utili-zation of BOF slag and MSWI ash testied that it can be used as po-tential materials in road construction for saving natural resources.
There are few researches about the use of different aggregatetypes in asphalt mixes. Ibrahim et al.  investigated the possibil-ity of improving the properties of local asphalt concrete mixes byreplacing different portions of the normally used limestone aggre-gate by basalt. The replacement included total replacement of thelimestone by basalt, replacing the coarse aggregate, and replacingthe ne aggregate. Results showed that the optimal mix was themix that had basalt coarse aggregate and limestone ne aggregate.In order to overcome the stripping potential of the optimal mix,20% of the ller portion of the aggregate, material smaller than0.075 mm, was replaced by lime. The optimal mix showed superi-ority, over the tested mixes, in all the evaluated properties. How-ever, the use of different rock aggregates in SMA is not studied indetail yet.
The coarse aggregate for SMA mixtures needs to be angular,cubical, and hard. Because basalt is harder than limestone, usingbasalt aggregate is preferred than using limestone in SMA [3,11].Since limestone aggregate is cheaper than basalt aggregate inChina, we try to use partial limestone aggregate in SMA by replac-
W. Cao et al. / Construction and Bing ne aggregate portions of the normally used basalt aggregateby limestone. The main objective of this research was to comparethe performance of SMA mixtures using basalt and limestone are shown in Table 2.
2.1.2. Asphalt binderSBS modied asphalt binder supplied by a commercial petroleum company was
used in laboratory. Properties of SBS modied asphalt binder are shown in Table 3.The results meet specications for modied asphalt binders .
2.1.3. Other materials usedThe mineral ller used was limestone powder, which was passed through the
#200 sieve. Wood ber as a drainage inhibitor for asphalt binder was applied inSMA mixtures. The performance indexes of the two materials meet the technicalrequirements of specications .
2.2. Mix design
According to the specications for construction of highway asphalt pavementsof China , a nominal maximum size 13.2 mm SMAmixture was used for the mixdesign in this study. To achieve the comparability of performance evaluation ofthree kinds of SMA mixtures (B-SMA, L-SMA, and BL-SMA), the principle of thesame coarse skeleton structure, the same asphalt content, and the similar volumet-ric parameters of compacted mixtures was applied in mix design. The design proce-dure used in the paper was as follows:
(1) The median gradation of specications  was chose as the initial grada-tion of B-SMA, L-SMA, and BL-SMA, respectively.
(2) Based on the estimation of optimum asphalt content range and eld expe-rience [3,14], the asphalt content of three SMA mixtures used in the exper-iment was determined to 5.90%.
Table 1Properties of coarse aggregates.
Properties Test values Specications
Apparent specic gravity13.216 mm 2.864 2.731 >2.609.513.2 mm 2.866 2.7334.759.5 mm 2.867 2.724
Bulk specic gravity13.216 mm 2.822 2.681 >2.509.513.2 mm 2.823 2.6874.759.5 mm 2.818 2.678
Water absorption (%)13.216 mm 0.35 0.51 62.09.513.2 mm 0.35 0.504.759.5 mm 0.43 0.53Crushed stone value (%) 10.0 19.9 626L.A. abrasion (%) 8.3 17.8 628
Percent of at and elongated particles (%)13.216 mm 7.4 11.0 6159.513.2 mm 8.2 10.5
4.759.5 mm 8.3 14.6Polished stone value (PSV) 51 45 P40
Where eB is failure strain; h is height of section at midspan; d is displacement at mid-span; and L is span of specimen. Obviously, the larger failure strain is the better ofthe performance of resistance to cracking in low temperature.
2.3.3. Indirect tensile test
Table 2Properties of ne aggregates.
Properties Test values Specications
476 W. Cao et al. / Construction and Building Materials 41 (2013) 474479(3) According to the procedures described in T0702-2011 , Marshall spec-imens of three kinds of SMA mixtures were fabricated and the volumetricparameters of compacted mixtures were calculated.
(4) To achieve the target air voids of 3.5%, we repeatedly adjusted the tails(2.500.30.6 mm 2.848 2.7100.150.3 mm 2.846 2.7100.0750.15 mm 2.844 2.715
Angularity (%)2.364.75 mm 29.5 220.127.116.11 mm 33.8 30.1 0.61.18 mm 33.3 35.0The higher DS of asphalt mixtures is the better of the performance of resistanceto permanent deformation in high temperature.
2.3.2. Beam bending testThe performance of resistance to cracking in low temperature test, i.e., beam
bending test at 10 C according to China Standard T 0715-2011  was per-formed using UTM-100. The specimens, which were 250 mm 30 mm 35 mmrectangular beam, were fabricated by cutting the rutting test specimens mentionedpreviously along a rolling direction. The loading velocity was 50 mm/min and thedisplacements were measured using a linear variable displacement transducer.The failure strain can be calculated using Eq. (2) as follows :
Table 3Properties of SBS modied asphalt binder.
Index Specic gravity (15 C) Penetration (25 C, 0.1
Test values 1.031 45The freezethaw indirect tensile test which is nearly equivalent AASHTO T283was done as per the procedure in standard test method T0729-2000 . This testanalyzes the impact of saturation and immersion of the mix in water on the resis-tance to indirect tensile strength in Marshall specimens. Eight specimens were pro-duced for every type of mix under study, separating the specimens subsequentlyinto two groups in order to obtain a similar density. One group was tested in theindirect tensile loading in dry conditions, the other was moisture conditioned priorto loading. The moisture conditioning involved a freezethaw cycling, in which thesaturated specimen with 7080% degree of saturation was covered tightly with aplastic wrap and placed in a freezer bag containing 10 ml water. The sealed freezerbag containing specimen was then placed in a freezer at about 18 C for a mini-mum of 16 h. After removing from the freezer, the specimen was placed into a60 C water bath for 24 h. Prior to indirect tensile loading, the conditioned specimenwas moved from the hot water bath to another water bath at 25 0.5 C for about2 h to bring the specimen to the testing temperature.
The indirect tensile strength ratio (TSR) was expressed as the ratio of the origi-nal strength that was retained after the moisture conditioning using Eq. (3) as fol-lows :
Where TSc is average indirect tensile strength of conditioned group, and TSd is aver-age indirect tensile strength of dry group.
The higher the TSR value is, the higher the resistance to moisture damage is andthe lower the moisture susceptibility is of the asphalt mixture.
2.3.4. Dynamic modulus testTests were carried out as per AASHTO TP62  using simple performance tes-
ter shown in Fig. 3...