Waste plastic utilization in asphalt mix for sustainability and enhancing rheological parameters

The demand for resilient and sustainable pavements capable of accommodating increased traffic loads necessitates innovations beyond traditional approaches. While the Marshall mix design remains widely used in Bangladesh, evolving transportation pressures call for performance enhancements that also address environmental concerns. This study explores the dual challenge of waste plastic management and asphalt performance improvement through the incorporation of shredded polyethylene terephthalate (PET) from discarded water bottles. Utilizing a dry mixing process, twenty-five combinations of bitumen and PET content were evaluated. The results revealed a notable increase in Marshall stability, reaching 2738 lb. with 7.5 % PET representing a 31.8 % improvement over the control mix. The findings demonstrate that PET addition significantly improves rheological properties while maintaining flow within acceptable limits. This approach, relying on untreated, larger-sized PET particles, presents a practical, low-cost, and scalable solution particularly suited for developing regions where Marshall methodology predominates and Superpave infrastructure remains limited.