Viability of reducing plastic waste disposal by utilization in hot mix asphalt: a multicriteria analysis with cost considerations.

Plastic waste is a non-biodegradable material which is extensively used in many applications, creating a critical environmental challenge of its disposal. Therefore, its utilization in large quantities as a recycled product in road infrastructure will mitigate ill effects occurring because of its dumping. 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 the Marshall mix design procedure in the context of Pakistan. A data-driven framework is employed with a novel multivariate performance score function. Incorporation of RPWA, sourced from LDPE polyethylene bags, at the content of 2.5% by weight (~ 6% by volume) was found to provide the best 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. The findings of this study highlight the impacts of using RPWA in road infrastructure providing ways to reduce plastic pollution through optimum design of pavements. However, they are based on Marshall laboratory testing and require validation through durability, moisture, rutting, fatigue, and field studies before implementation.