Indirect performance comparison for styrene–butadiene–styrene polymer and fatty amine anti-strip modified asphalt mixtures

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<ul><li><p>renal</p><p>t, 61nt, 6olleg</p><p>Received 28 August 2011Received in revised form 14 October 2011Accepted 24 November 2011Available online 29 December 2011</p><p>this study is to analyze effects of SBS polymer and fatty amine anti-stripping agent additives for asphalt</p><p>asphalt concrete pavements. Water causes loss of adhesion at thebitumenaggregate interface. This premature failure of adhesionis commonly referred to as stripping in asphalt concrete pave-ments [1].</p><p>Moisture damage or stripping is an asphalt pavement distressthat is generally recognized as the loss of the bond between theasphalt binder and the aggregate. Several pavement distresses that</p><p>result in reduced HMA shear strength. Hot-mix asphalt strippingevaluation is a source of signicant industry discussion and debate.Transportation agencies use a number of methods to evaluatestripping, with many methods customized depending on local con-cerns and environmental conditions [4].</p><p>Moisture damage of asphalt mixes, better known as stripping, isa major distress affecting pavement performance. AASHTO T283has historically been used to detect moisture susceptible pave-ments through the determination of a tensile strength ratio(TSR). Results from AASHTO T283 have been inconsistent. As aresult there has been increased interest in nding an alternative</p><p> Corresponding author. Tel.: +90 462 7717250; fax: +90 462 7717251.E-mail addresses: eroliskender@gmail.com (E. Iskender), aaksoygmf@hotmail.</p><p>Construction and Building Materials 30 (2012) 117124</p><p>Contents lists available at</p><p>B</p><p>evcom (A. Aksoy), ozenh@u.edu (H. Ozen).1. Introduction</p><p>Environmental factors such as temperature, air, and water canhave a profound effect on the durability of asphalt mixtures. Inmild climatic conditions where good-quality aggregates andasphalt cement are available, the major contribution to the deteri-oration may be trafc loading, and the resultant distress manifestsas fatigue cracking, rutting (permanent deformation), and raveling.However, when a severe climate is in question, these stressesincrease with poor materials, under inadequate control, with trafcas well as with water which are key elements in the degradation of</p><p>can include stripping as the underlying cause are rutting, cracking,raveling, ushing, and bleeding. Stripping can progress from eitherthe top or bottom of hot mix pavement layer. The common cause inall cases of stripping is the presence of water. The potential for ahot mix asphalt pavement to incur moisture damage can be con-trolled or reduced through material selection, mixture designs thatinclude a high asphalt lm thickness, additives, proper pavementdesign, construction, compaction, and drainage [2,3].</p><p>Permanent deformation and moisture damage (i.e., rutting andstripping) are two predominant hot-mix asphalt (HMA) distresses.Rutting can be caused by many factors, including stripping, whichKeywords:Asphalt mixturesSBS polymerAnti-stripping agentFatty amineRepeated creepResilient modulusIndirect tension testMoisture damage0950-0618/$ - see front matter 2011 Elsevier Ltd. Adoi:10.1016/j.conbuildmat.2011.11.027mixtures. Indirect performance comparison was evaluated with such additives. SBS and amine agentswere compared with indirect effects in context with deformation and moisture resistance. Three typesof moisture conditioning were selected. Regimes were based on water immersion, freezethaw cyclesand superposition of these. Repeated creep tests (RCTs) and indirect tensile (ITT) tests were applied. Inview of RCT polymer showed higher resistance to rutting based on permanent deformations than the con-trol and amine modied mixtures. Lower deformations were calculated with SBS than the others accord-ing to the RCT. For high temperature and combined moisture effects based on water saturation andfreezethaw cycle rutting and moisture problem have been being a serious problem for both controland SBS-anti stripping agent modied mixtures. In this context great importance must be given in designand quality control. Proportional moisture damage evaluation was found as a coniction. With theincreasing of rise period lower resilient modulus (RM) were obtained with all control and modied mix-tures in ITT. Selected moisture conditioning methods reveal observable level of damage with the RM test(ASTM D4123) with the selected parameters. Both amine and SBS modied mixtures gives higher RMhence load spreading capacity increases with both SBS and anti-strips.</p><p> 2011 Elsevier Ltd. All rights reserved.Article history: Rutting and moisture damage are two important distress mechanisms for asphalt mixtures. The aim ofIndirect performance comparison for styand fatty amine anti-strip modied asph</p><p>Erol Iskender a,, Atakan Aksoy b, Halit Ozen caKaradeniz Technical University, Of Faculty of Technology, Civil Engineering DepartmenbAvrasya University, Engineering and Architectural Faculty, Civil Engineering Departmec Florida International University, Department of Civil and Environmental Engineering, C</p><p>a r t i c l e i n f o a b s t r a c t</p><p>Construction and</p><p>journal homepage: www.elsll rights reserved.ebutadienestyrene polymert mixtures</p><p>830 Trabzon, Turkey1010 Trabzon, Turkeye of Engineering and Computing, Miami, FL, United States</p><p>SciVerse ScienceDirect</p><p>uilding Materials</p><p>ier .com/locate /conbui ldmat</p></li><li><p>test. Preliminary indications reveal that loaded wheel rut testers,such as the Asphalt Pavement Analyzer (APA) have the potentialto detect moisture susceptible mixtures. To date, no standard testmethodology has been developed [5].</p><p>Stripping can result include rutting and cracking due to shearforces. Although the phenomenon of stripping has been acknowl-edged for over 50 years, being able to predict the moisture suscep-tibility of aggregates has not been adequately solved. Part of the</p><p>the test is also time intensive (34 days to complete). Thus, a test</p><p>One conventional bitumen and two different types modied bitumen was pre-pared. Styrenebutadienestyrene elastomeric polymer (SBS) and fatty amine agent(AS) were used for modication of the selected asphalt mixtures.</p><p>SBS concentration was chosen as 5% by weight of AC. It was stated that a signif-icant improvement in the properties of base bitumen was observed when the SBScontent was increased from 2% to 6% by weight [7]. The base bitumen was heatedto uid condition (180 C) temperature and the powder form SBS was then addedslowly to the base bitumen. The mixing process continued for 2 h at constanttemperature.</p><p>AS is a liquid additive, specially designed for hot-mixed asphalt where goodheat stability is required. The dosage of AS depends on the type of bitumen andaggregate used. Normally between 0.2% and 0.5% is added to the binder [8]. Onthe other hand AS concentration was chosen as 0.4% by weight of bitumen andadded asphalt binder. The conventional properties of AS modier were presentedin Table 4.</p><p>Wearing coarse design was realized with ASTM D1559 Marshall Method.Optimal mixture parameters were presented in Table 5 according to the Marshalltest.</p><p>Properties of the used samples in experimental stages were illustrated in Tables68. Tables 68 show control samples, SBS and AS modied samples respectively.</p><p>Table 2Aggregate specic gravities (g/cm3).</p><p>Grain-size fraction Apparent specic gravity Bulk specic gravity</p><p>Coarse aggregate 2.894 2.832Fine Aggregate 2.889 2.751Filler aggregate 2.910 Aggregate mixture 2.893 2.803</p><p>0</p><p>10</p><p>20</p><p>30</p><p>40</p><p>0.01 0.10 1.00 10.00 100.00</p><p>Sieve Size, mm</p><p>Perc</p><p>enta</p><p>g</p><p>Fig. 1. Aggregate distribution on gradation chart.</p><p>Table 4Conventional properties of AS modier [8].</p><p>Properties Value</p><p>Appearance at 20 C Brown, viscous liquidOdor Amine-likeDensity at 20 C, kg/m3 980Pour point, C 218 CViscosity, dynamic at 20 C 505 mPa s</p><p>118 E. Iskender et al. / Construction and Building Materials 30 (2012) 117124method that would accurately predict stripping potential and takehours rather than days to complete would be attractive to highwayagencies and contractors [5].</p><p>Stripping may occur from separation of the asphalt lm andaggregate surface or from emulsication of the asphalt. This phe-nomenon has been recognized since 1938. A number of tests areused to evaluate moisture susceptibility of bituminous mixtures.In addition to AASHTO T283, these tests include the following:NCHRP Report 192 (Lottman), Modied Lottman, NCHRP Report274 (Tunnicliff and Root), ASTM D 1075-81 (AASHTO T 165-82),ASTM D 1664-80 (AASHTO T 182-82), and MIL-STD-620ImmersionCompression Test. Someof these tests are based on sub-jective evaluation of results. In general, the tests have a tenuous cor-relation with actual eld performance [6].</p><p>To alleviate or to control the deformations due to water damage,various researches were performed leading to the utilization ofanti-stripping additives. Anti-stripping additives are used toincrease physico-chemical bond between the bitumen and aggre-gate and to improve wetting by lowering the surface tension ofthe bitumen. The additives that are used in practice or tested inthe laboratory include: (i) traditional liquid additives, (ii) metalion surfactants, (iii) hydrated lime and quick lime, (iv) silane cou-pling agents, and (v) silicone. Among them, hydrated lime andquicklime are the most commonly used solid type anti-strippingagents [1].</p><p>The main goal of this research is to investigate rutting andmoisture damage problems in asphalt mixtures. Anti-strippingfatty amine additive (AS) and styrenebutadienestyrene polymer(SBS) was used. Repeated creep tests and indirect tension testswere realized for different moisture conditioning. Proportionalevaluation for stripping was studied and permanent deformation.</p><p>2. Materials</p><p>Test materials and experimental procedures in this study were following.Aggregate combination and asphalt cement (AC) as bitumen were used. Aggregatecombination was obtained from the Sularbasi rock quarry near Arakl, Trabzon, Tur-key. Several properties of coarse and ne aggregates were exhibited in Tables 1 and2. Fifty to seventy penetration grade AC was used. Bitumen test results were pre-sented in Table 3. Gradation curve are represented in Fig. 1.</p><p>Table 1Engineering properties of the used aggregate.</p><p>Properties Test method Value</p><p>L.A. Abrasion (%) ASTM C-131 9.6Flakiness (%) BS 812 (part 105) 14.7Stripping resistance (%) ASTM D-1664 3035Water absorption (%) ASTM C-127 0.85Soundness in NaSO (%) ASTM C-88 4.06attention of the Strategic Highway Research Program (SHRP) wasfocused on determining a test method to evaluate the moisturedamage potential of aggregates. This research was not completelysuccessful. The recommendations from SHRP were to continueusing AASHTO T283, Resistance of Compacted Bituminous Mix-ture to Moisture Induced Damage. Besides the occasional inabilityof AASHTO T283 to accurately determine moisture susceptibility,4</p><p>Polished stone value BS 812 (part 114) 0.60Plasticity index for sandy aggregate TS 1900 Non-plasticTable 3The results of tests performed on asphalt cement (AC 5070).</p><p>Properties Test method Unit Value</p><p>Specic gravity (25 C) ASTM D-70 g/cm3 1.019Softening point (C) ASTM D3676 C 52Flash point (Cleveland) ASTM D-92 C 210Penetration (25 C) ASTM D-5 0.1 mm 67Ductility (25 C) ASTM D-113 cm 100+</p><p>50</p><p>60</p><p>70</p><p>80</p><p>90</p><p>100</p><p>e Pa</p><p>ssin</p><p>g, %pH 11 at 5% solutionWater solubility Emulsiable</p></li><li><p>BuilTable 5Marshall design test results.</p><p>Design parameters Values Board in Turkey</p><p>Min. Max.</p><p>Bulk specic gravity, Gmb 2.510 Marshall stability (kg) 1530 900 Air voids, Pa (%) 4 3 5Void lled with asphalt, Vf (%) 72 75 85</p><p>E. Iskender et al. / Construction and3. Test methods</p><p>In this research SBS and AS modied asphalt mixtures wereevaluated with repeated creep test and indirect tension tests. Testswere done identical samples for both and modied ones. Controland conditioned samples were tested with the same parameters.Three different types of moisture conditioning systems wereapplied. In the rst conditioning conditioned samples were keptin 60 C water for 72 h. In the second system samples were locatedin 15 C freezer for 72 h with water bath and after samples werekept in water at room temperature. Plastic bags were used. These</p><p>Flow, F (1/100 in.) 3.2 2 4Filler/bitumen 1.17 1.5Asphalt cement, Wa 5.15</p><p>Table 6Properties of the control samples.</p><p>Samplenumber</p><p>Averageheight (mm)</p><p>Practicaldensity(g/cm3)</p><p>Max. T.density(g/cm3)</p><p>Airvoids(%)</p><p>VMA(%)</p><p>VFA(%)</p><p>1 59.9 2.523 2.618 3.6 14.4 74.92 59.9 2.523 2.618 3.6 14.4 74.93 60.1 2.519 2.618 3.8 14.6 73.94 60.7 2.518 2.618 3.8 14.6 73.85 61.8 2.533 2.618 3.2 14.1 76.96 60.8 2.528 2.618 3.4 14.2 75.97 60.6 2.530 2.618 3.4 14.2 76.38 61.1 2.517 2.618 3.9 14.6 73.69 60.0 2.528 2.618 3.4 14.2 75.9</p><p>10 60.6 2.523 2.618 3.6 14.4 74.811 60.1 2.526 2.618 3.5 14.3 75.512 60.3 2.530 2.618 3.4 14.2 76.313 60.3 2.528 2.618 3.4 14.2 76.014 59.3 2.525 2.618 3.5 14.3 75.315 60.3 2.530 2.618 3.4 14.2 76.216 59.3 2.529 2.618 3.4 14.2 76.1</p><p>Table 7Properties of the SBS modied samples.</p><p>Samplenumber</p><p>Averageheight (mm)</p><p>Practicaldensity(g/cm3)</p><p>Max. T.density(g/cm3)</p><p>Airvoids(%)</p><p>VMA(%)</p><p>VFA(%)</p><p>1 61.2 2.503 2.618 4.4 15.1 70.92 60.9 2.506 2.618 4.3 15.0 71.43 61.4 2.502 2.618 4.4 15.1 70.74 61.2 2.504 2.618 4.4 15.0 71.15 60.5 2.516 2.618 3.9 14.6 73.46 61.7 2.503 2.618 4.4 15.1 70.97 60.8 2.520 2.618 3.7 14.5 74.38 61.3 2.508 2.618 4.2 14.9 71.89 61.5 2.507 2.618 4.2 14.9 71.7</p><p>10 61.6 2.510 2.618 4.1 14.8 72.311 61.2 2.505 2.618 4.3 15.0 71.212 61.0 2.511 2.618 4.1 14.8 72.313 60.4 2.516 2.618 3.9 14.6 73.414 62.3 2.512 2.618 4.0 14.8 72.615 60.4 2.510 2.618 4.1 14.8 72.316 62.2 2.512 2.618 4.1 14.8 72.6Table 8Properties of the AS modied samples.</p><p>Samplenumber</p><p>Averageheight(mm)</p><p>Practicaldensity (g/cm3)</p><p>Max. T.density (g/cm3)</p><p>Airvoids(%)</p><p>VMA(%)</p><p>VFA(%)</p><p>1 60.1 2.528 2.618 3.4 14.2 75.92 61.3 2.511 2.618 4.1 14.8 72.53 60.5 2.511 2.618 4.1 14.8 72.44 60.4 2.518 2.618 3.8 14.6 73.75 61.2 2.514 2.618 3.9 14.7 73.16 60.6 2.525 2.618 3.6 14.3 75.27 60.4 2.516 2.618 3.9 14.6 73.48 61.0 2.504 2.618 4.4 15.0 71.19 61.2 2.508 2.618 4.2 14.9 71.8</p><p>10 61.6 2.507 2.618 4.2 14.9 71.711 61.1 2.504 2.618 4.4 15.1 71.012 60.6 2.515 2.618 3.9 14.7 73.213 60.8 2.516 2.618 3.9 14.6 73.414 60.8 2.502 2.618 4.4 15.1 70.615 60.7 2.521 2.618 3.7 14.5 74.416 60.9 2.511 2.618 4.1 14.8 72.3</p><p>Actuator </p><p>ding Materials 30 (2012) 117124 119processes were also repeated as three steps. At the last condition-ing rst and second damage models were come together and thirdconditioning model was developed. Both control and two differentmodied mixture samples were used. Repeated creep test andindirect tension test were applied both conditioned and uncondi-tioned samples and control and modied mixtures.</p><p>3.1. Repeated creep test</p><p>Repeated creep tests (RCTs) has been used to determine per-manent deformation of asphalt mixtures. RCT were applied tocontrol and modied mixture samples. RCT tests were studiedin Nottingham Asphalt Tester (NAT). Test frame in NAT testerwas illustrated in Fig. 2. Repeated creep test parameters weresummarized in Table 9.</p><p>3.2. Indirect tension test</p><p>The resilient modulus is a non-destructive test that can be usedto evaluat...</p></li></ul>

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