Utilization of Recycled Plastic in Hot Mix Asphalt: A Performance and Viability Study

Plastic waste is a non-biodegradable material which is produced in large quantities globally due to extensive use of plastic products. Consequently, its disposal in the natural environment (land or sea) creates hazardous impacts on it. The matter is more grievous in developing countries which do not have proper systems for waste collection and recycling. Hence, there is a critical need for research to explore its use after recycling in suitable applications. The aim of this study was to analyze the impacts of adding Recycled Plastic Waste Aggregate (RPWA) in Hot Mix Asphalt (HMA) mixes using a wide range of variables by employing Marshall mix design procedure. A data-driven framework is employed with a novel multivariate performance score function. Incorporation of RPWA, sourced from LDPE polyethylene bags, at a precise content 2.5% by weight (~6% by volume) was identified as the optimal dosage in terms of strength while fulfilling criteria of other key parameters. The mix performance degrades steeply and significantly beyond 2.5% but remains under acceptable design ranges till 10%. Based on these results, RPWA can be used to enhance pavement performance with strict quality control on batching. The findings of this study pave the way towards a sustainable pathway for high-volume disposal of low-value plastic film waste with applications in low to medium-traffic roads. Investigations with smaller increments in RPWA content, field testing and Lifecycle Cost Analysis (LCCA) are recommended for future research directions.