Laboratory performance of sustainable stone matrix asphalt mixtures utilizing electric arc furnace slag and waste plastic

This research examined the feasibility of incorporating electric arc furnace (EAF) slag and waste plastic into stone matrix asphalt (SMA) mixtures. With annual global production of over 70 million tons of EAF slag and 300 million tons of plastic waste, repurposing these materials could yield substantial environmental benefits. The research evaluated SMA mixtures with EAF slag as aggregate replacement and waste plastic as a binder modifier. The research aimed to develop sustainable SMA formulations while promoting recycling of industrial byproducts. Laboratory experiments were conducted to evaluate mix design characteristics, drain-down potential, abrasion resistance, rutting resistance, moisture susceptibility, fatigue performance, and stiffness of modified SMA mixtures. The addition of waste plastic, ranging from 4%, 6%, 8% and 12% by weight of bitumen, demonstrated significant improvements in key properties. Results showed that waste plastic reduced the optimum binder content and increased voids in the mineral aggregate. EAF slag mixtures demonstrated improved drain-down characteristics and moisture susceptibility. Both rutting resistance and fatigue life increased significantly with waste plastic content, with EAF slag mixtures consistently outperforming those made with conventional aggregates. Ultrasonic pulse velocity tests indicated higher stiffness in modified mixtures. The optimal waste plastic content was determined to be 8% by weight of bitumen. Statistical analysis confirmed significant effects of both EAF slag and waste plastic on multiple performance parameters. These findings highlight the potential of incorporating industrial byproducts into SMA mixtures to achieve high-performance road construction solutions, offering a viable pathway for addressing global waste management challenges.