PERFORMANCE EVALUATION OF WASTE EXPANDED POLYSTYRENE MODIFIED ASPHALT MIXTURES CONTAINING HIGH RAP CONTENT

Abstract

Waste is generated in large quantities today on a global scale. Expanded Polystyrene (EPS) is one of these waste plastic materials that can be used to produce more durable, costeffective, and eco-friendly pavements. Tons of asphalt have been squandered because of the reconstruction and resurfacing of numerous roads in Pakistan, including highways and motorways. By wasting the massive amount of Reclaimed asphalt pavement (RAP), natural resources and a significant portion of our revenue are depleted. This study evaluates a laboratory investigation to assess mix designs with varying amounts of waste Expanded Polystyrene, including 2%, 4%, 6%, and 8%, combined with the high Reclaimed Asphalt Pavement (RAP) content, including 20%, 40%, and 60%, under various performance situations. Utilizing the Marshall Stability Test, Double Wheel Tracker Test, and Indirect Tensile Strength Test, this study observed the stability, flow, rutting potential, tensile strength, and moisture damage characteristics of the controlled and Modified HMA mixtures. Preliminary testing on WEPS-modified bitumen revealed that bitumen hardened with the addition of Waste Expanded Polystyrene (WEPS). By evaluating the outcomes of physical tests on WEPS-modified bitumen, the optimum WEPS content of 4% was established. WEPS and RAP-modified asphalt mixtures showed better performance in terms of stability, flow, tensile strength, and rutting resistance compared to the controlled mixture. WEPS-modified HMA outperformed virgin HMA in terms of moisture susceptibility. However, raising the RAP content above 40% led to a significantly lower TSR value than the control mix, which implies a higher risk of moisture damage in HMA mixtures. In addition to having a longer service life and being environmentally beneficial, WEPS-modified HMA pavements with high RAP content offer a cost-effective alternative for constructing and maintaining high-volume roads.