Experimental Investigation of Nano Materials Applicability in Hot Mix Asphalt (HMA)

Abstract

Pakistan is leading towards a major motorway and highways system, and most of the roads are flexible pavements that have a higher susceptibility to Fatigue and Rutting. The utilization of Nano materials in Hot Mix Asphalt (HMA) can significantly improve the performance indicators in the form of extension in pavement service life and decrease pavement distresses. The Nano materials reinforcement of HMA can enhance pavement performance indicators, including low and high-temperature dynamic modulus and stability and enhancement in rut resistance and stiffness modulus. Nano Materials modified is a suitable solution to improve the mechanical properties of HMA. The current study objectives focus on the experimental investigation of Nano Materials such as Carbon Nano Tubes (CNT) and Nano Clay (NC) applicability in HMA. CNT and NC percentages used in HMA to the weight of bitumen are 0.5%, 1.5%, 2.5% and 2%, 4%, 6%, 8%. Conventional and Nano material modified asphalt mixes were subjected to performance tests such as SPT, Dynamic Stability and Rutting, Tensile Strength Ratio (TSR), and Resilient Modulus (MR) using UTM-25. Results have indicated that the addition of CNT and NC has improved HMA properties such as enhancement in dynamic modulus and dynamic stability and improves stiffness, rut resistance, and moisture resistance. It has been observed that 1.5% CNT with 6% NC content by weight of bitumen in asphalt mixtures outperformed other CNT and NC percentages. Moreover, Dynamic stability and Rut resistance have been improved by 820% and 64.7%, respectively, while resilient modulus increased by 309% and moisture susceptibility has been reduced by 22.26%, respectively. Overall, the asphalt mixtures with 1.5% CNT with 6% NC content has the best results.