Effect of Adding LDPE Bags on Rutting and Stripping Behaviour of Asphalt Mix

Disposal or incineration of waste low-density polyethylene (LDPE) bags is a major problem, as it causes pollution. The pavement over time gets deteriorated by vehicular traffic, which mostly results in rutting and other distresses. This research is based on the performance evaluation of hot mix asphalt (HMA) modified with LDPE. Aggregates National Highway Authority Pakistan (NHA) gradation B, bitumen grade 60/70 and waste LDPE bags from the dump yards of Islamabad (Pakistan) were used in this study. Penetration, ductility and softening-point tests were conducted with bitumen modified with different contents of waste LDPE bag flakes; i.e., 0%, 2%, 4%, 6% and 8% to figure out the optimum modifier content (OMC). Marshall testing was performed for the determination of optimum bitumen content (OBC). Using OBC and incorporating LDPE contents as a replacement for OBC, HMA samples were tested for performance evaluation, including rutting resistance and moisture susceptibility and compared with the performance of unmodified HMA. It was observed that 4% of LDPE as a replacement for OBC in the HMA can be used as OMC and yielded better performance results than unmodified asphalt mix. Rutting resistance was improved by 20.86% and tensile strength ratio (TSR) for moisture susceptibility evaluation was above the specified limit of 80%. KEYWORDS: Waste LDPE bags, Low-cost bitumen modifier, Performance evaluation, Performance improvement, Cost comparison, Sustainable environment.