Performance Evaluation of Asphalt Mixtures with Tire Rubber Modified Binder
AdvisorSebaaly, Peter E.
Civil and Environmental Engineering
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Waste tire is a worldwide problem. One effective solution for recycling scrap tires is to use them as an asphalt modifier for paving applications.The necessity of recognizing the performance of terminal blend tire rubber modified asphalt binder (TTR) hot mix asphalt (HMA) mixtures is imperative to keep improving the overall conditions of the roads built using this modifier. This study is based on assessing the performance of TTR compared with neat asphalt binder when used in paving applications.The objectives of this study were to evaluate the engineering properties and performance characteristics of TTR asphalt mixtures relative to the asphalt mixtures manufactured with neat asphalt binder. The study evaluated two Field Mix Lab Compacted (FMLC) and three Lab Mix Lab Compacted (LMLC) HMA mixtures. Mix designs were performed for the three types of asphalt binder including two TTR, and one neat asphalt binder; with 1.5% by dry weight of aggregate (dwa) lime content applied using the marination process; and 25% of RAP content. The mix designs were conducted following the Superpave standard method and evaluated using Tensile Strength Ratio (TSR) criteria for moisture sensitivity. The type of binder played a role in the determination of the optimum binder content. The TSR for all mixtures were greater than 90% which indicates that the asphalt mixtures designed are not susceptible to moisture damage. Performance of HMAC mixtures was evaluated by means of dynamic modulus master curves, fatigue cracking, permanent deformation, and reflective cracking resistance. Dynamic modulus tests were conducted using the Asphalt Mixture Performance Tester (AMPT) device and the master curves were built using AASHTO R84 standard procedure for asphalt mixtures. Flow Number tests were conducted using the Asphalt Mixture Performance Tester (AMPT) device and the results were used to fit the Francken Model as specified in AASHTO T387. Fatigue cracking resistance tests were conducted using the Hydraulic Beam Fatigue Machine and the results were used to find the cycles to failure according to AASHTO T321. Reflective cracking resistance were conducted with the Texas Overlay Machine and the results were analyzed using the Test Procedure for Overlay Test Tex-248-F. TTR HMA mixtures exhibited a better cracking resistance when compared when neat asphalt binder HMA.