Evaluation of mechanical responses of asphalt mixtures incorporating plastic waste as additives by different compaction efforts and mixing temperatures for a sustainable mixture.

Sustainable pavement is essential for country development, offering durable, environmentally friendly, and cost-effective infrastructure. For Malaysia, sustainable pavement supports Sustainable Development Goals (SDGs) 9 and 11 while addressing road deterioration caused by increasing traffic volumes and loads. This deterioration shortens pavement service life and necessitates frequent maintenance, driving the need for innovative solutions. To enhance pavement sustainability, researchers have explored additives like plastic waste, specifically low-density polyethylene (LDPE), a major component of packaging waste. LDPE improves durability but is prone to fatigue cracking. Addressing this, physical treatments of LDPE can improve its surface topography, compaction properties, and binder-aggregate adhesion, optimizing pavement performance. This study evaluated hot mix asphalt mixtures incorporating untreated plastic (UP) and treated plastic (TP) additives under varied compaction efforts and mixing temperatures. Performance tests, including Marshall stability, resilient modulus, creep, and tensile strength ratio (TSR), were conducted. Results showed that the TP50L mixture (with 25% fewer compaction blows and a mixing temperature reduced by 25 °C) performed better than the UP and control mixtures, demonstrating 30% greater fatigue resistance, 11% higher rutting resistance, and 12% improved moisture damage performance. The superior performance of TP additives is attributed to their rougher surface, enhancing the binder-aggregate bond and aggregate properties. The study concludes that treated plastic additives not only strengthen pavements against permanent deformation but also reduce compaction efforts and mixing temperatures, leading to lower energy use during construction. By incorporating plastic waste into pavements, this approach promotes environmental sustainability, reduces maintenance needs, and supports eco-friendly infrastructure development.