Performance of Waste Plastic Aggregate (WP) Modified Stone Mastic Asphalt Mixtures

Plastic waste pollution is a growing environmental concern, and this research explores using manufactured aggregate with recycled plastic (WP) in asphalt mixture as a sustainable solution to tackle this challenge. The high-density polyethylene (HDPE) waste plastic was blended with oxidized grinding waste (Fe₃O₄) from steel profiling operations, as a substitute for coarse aggregates in Stone Mastic Asphalt (SMA). SMA mixtures incorporating 3%, 5%, and 10% WPA were evaluated for their stiffness, volumetrics, resistance to fatigue cracking, and deformation resistance. The findings reveal that mixtures containing 3% and 5% WP achieved stiffness values higher than conventional SMA (control Mix). However, mixtures with 10% WP exhibited a notable decline in stiffness, impacting overall structural performance had slightly higher tensile strains than the control but better load cycle resistance. The 10% WP had the lowest fatigue resistance. Rutting resistance was very good with the 3% WP mixture, which showed the lowest axial strain. All 3% and 5% WP mixtures had improved rutting resistance compared to the control, but the 10% WP mixtures exhibited higher strain rates, indicating increased susceptibility to rutting. These findings highlight the potential of consuming large quantify of recycled plastic in asphalt mixtures, offering a sustainable solution for plastic waste management and promoting eco-friendly road construction practices.