Effect of Low-Density Polyethylene Waste on Volumetric Parameters and Moisture Susceptibility of Asphalt Mixtures

The use of waste materials in asphalt mixtures has become a popular way of promoting sustainability and reducing environmental impact. Waste plastic is one such material, a major component of solid waste which is abundantly available and disposed of without proper treatment. Waste plastic was found to be an effective modifier for bitumen mixes to be used in flexible pavements. Plastic roads can prove to be a boon for India’s extremely hot and humid climate, where ambient temperatures frequently cross 50°C, and heavy rainfall create major moisture damage in pavements. Low-density polyethylene (LDPE) plastic waste is one such material that has been investigated as a potential additive in asphalt mixtures. In this research, LDPE waste plastic of size less than 2.36 mm is used to modify the bituminous mixture using a dry process. The objective of the study is to compare volumetric parameters of waste plastic asphalt mixture with control asphalt mixtures and to evaluate the effect of LDPE waste plastic on moisture susceptibility of asphalt mixtures. The waste plastic was mixed with the aggregates at 155°C−160°C for proper coating of waste plastic on the aggregates, and the coating was quantified using MATLAB software. In this study, an attempt is made to quantify the reduction in optimum binder content due to the coating of waste plastics on the aggregate surface. Waste plastic-based asphalt mixes showed improved resistance to moisture susceptibility than the control mixture.