The Use of Recycled Plastic in Asphalt Pavements: Feasibility Study

Authors

Document Type

Article

Citation

Bueno, I.M., Rea, R.C., and Teixeira, J.E.S.L. (January 2026). The Use of Recycled Plastic in Asphalt Pavements: Feasibility Study. NDOT Research Report SPR-FY24(027).

Abstract

The plastics industry has been actively exploring new end-market opportunities for the more than 35 million tons of waste plastics generated annually. The use of recycled WP in asphalt presents an opportunity to improve pavement performance while reducing the growing amount of WP being landfilled or released into the environment. However, the use of WP in asphalt mixtures poses challenges due to variations in plastic composition and the presence of non-plastic contaminants. The absence of standardized procedures has resulted in inconsistent integration methods and unclear roles of WP within asphalt concrete (AC) mixtures. Therefore, the goal of this multiphase study is to evaluate the feasibility of using recycled plastics in asphalt mixtures. This Phase 1 study focused on the dry process, assessing the differences on the physical and chemical characteristics of various WPs, checking the effects of different laboratory mixing protocol to produce WP-modified mixtures, and investigating bonding mechanisms at the binder–aggregate interface when WP was added to pre-heated aggregates. Performance-based parameters from the Hamburg Wheel Tracking Test (HWTT) and the Indirect Tensile Asphalt Cracking Test (IDEAL-CT) were compared. Results showed that WP-modified mixtures produced with higher aggregate pre-heating temperatures exhibited enhanced rutting and moisture-damage resistance while maintaining short-term cracking resistance compared to a reference (no WP) mix. When comparing two different types of WP (LDPE and PP), both improved moisture-damage resistance, with LDPE demonstrating superior performance. Bonding tests revealed that aggregates coated with WP exhibited reduced water wettability and increased binder–aggregate bonding strength. At the end, the practical implementation of a WP-modified mixture was further evaluated in a field project. A Nebraska Superpave Recycled Mixture (SPR) using 25% RAP incorporating 1% post-consumer LDPE was produced at an asphalt plant and used in a local paving project in South Sioux City, Nebraska. Comparisons between laboratory- and plant-produced mixtures confirmed the feasibility of producing WP-modified mixtures and the validity of the mixing procedure adopted in the lab, with similar performance tests results. Overall, the mixtures exhibited improved rutting and moisture resistance while maintaining short-term cracking resistance. Future work will focus on the long-term performance evaluation and field monitoring of WP-modified mixtures, as well as assessing their recyclability potential.