Performance Evaluation of Styrene Butadiene Styrene and Nano-Clay Modified Asphalt Concrete Mixtures

Abstract

Asphaltic materials are extensively used in construction of highways around the globe, owing to low initial cost compared to other materials. However, flexible pavements’ propensity to rutting and fatigue cracking reduces its service life and necessitate quick repairs. The utilization of polymers and nanomaterials in Hot Mix Asphalt (HMA) is one of current research focus and have shown improvement in its performance by enhancing service life and decreased pavement distresses, such as rut resistance, stiffness modulus and resistance to moisture damage. Polymer and nano modified asphaltic materials are suitable solution for improvement of mechanical properties of HMA. This study focusses on the experimental evaluation of SBS and Nano-clay (NC) applicability in HMA, by incorporating 4.5% and 2%, 4%, 6%, 8% to the weight of bitumen respectively. Control and modified asphalt mixes were subjected to performance tests, such as Resilient Modulus (MR), Indirect Tensile Strength and Hamburg Wheel Tracking Test. Results indicates that addition of SBS and Nano-clay has improved the HMA stiffness, rut resistance and moisture resistance. It has been observed that 4.5% SBS with 6% NC content by weight of the binder content in mixture outperformed the other percentages of the modifier materials evaluated in the study, where rut resistance and Resilient Modulus have been improved by 39% and 40%, respectively, while moisture susceptibility has been reduced by 22.6%.