Rutting Resistance of Agricultural-Waste-Plastic Based Modified Bitumen

Rutting is a common issue in heavily trafficked roads, which can lead to further unrecoverable permanent deformation. This distress commonly occurs on roads with low-speed traffic and high-temperature environments. A better rutting resistance pavement is favorable because it will require lower maintenance and thus be more economical and ecologically friendly. The utilization of agricultural waste plastic (AWP) as a modifier for bitumen in road construction presents a sustainable solution for both plastic waste management and road durability enhancement. This study investigated the effect of incorporating agricultural waste plastics into bitumen using a low shear mixing method. The primary objective of this study is to assess the impact of agricultural plastic waste on the rutting resistance of modified bitumen. The modification process was carried out at a temperature of 160-180°C and a mixing speed of 500 rpm. Four types of bitumen were used in this study: standard 60/70 pen bitumen and 6% AWP-modified bitumen at three different shear mixing durations. Standard test results indicated that the inclusion of agricultural waste plastic dramatically changed the rheological properties of bitumen in terms of penetration number and R&B softening point. A further in-depth observation of the rheological properties of bitumen shows its enhanced capability in preventing potential rutting damage compared to conventional bitumen. The modified bitumen exhibited a higher complex modulus (G*) and lower phase angle (δ) at reduced frequency. The master curves explain the changes in the modification effect with temperature. The improved performance under higher temperatures and stress conditions or increased stiffness and elastic recovery can be attributed to the successful modification by agricultural waste plastic.