Pavimentazioni stradali sostenibili: valutazione delle prestazioni di conglomerati bituminosi a caldo composti da materiali riciclato e bitume modificato con rifiuti di plastica

This study investigates an environmentally friendly approach to assess the effect of recycling different percentages of highly heterogeneous mixed plastic waste derived from municipal sources in Milan, Italy, which is not conventionally recyclable. A reference bituminous mixture was compared with modified mixtures containing plastic waste (4% and 8% by binder weight), 25% reclaimed asphalt pavement as aggregate replacement, and combined mixtures with both materials. Plastic waste was incorporated using dry and wet processes, and the incorporation method showed clear effects on asphalt performance based on physical-mechanical laboratory tests. Modified mixtures demonstrated improved stiffness, durability, stability, tensile strength, and cracking resistance compared to the control mixture. Increasing plastic content from 4% to 8% further enhanced stiffness. Leaching tests showed no detectable heavy-metal release, confirming chemical stability. These results indicate that the proposed mixtures are a sustainable and viable alternative for road pavements, suitable for full-scale application with minimal environmental risk.