Sustainable dual-restoration of self-healing and drainage capabilities in porous asphalt mixture with iron tailings via microwave treatment

This study investigates the microwave-healing behavior of iron tailings asphalt mixture (ITAM) to support sustainable pavement engineering, focusing on macro- and meso -scale performance evolution under damage-healing cycles. The physicochemical properties of iron tailings were characterized, and microwave heating, multi-cycle damage-healing tests, and road performance evaluations were conducted to identify the optimal replacement ratio. CT combined with seepage simulations quantified meso -structural changes in fissures, void connectivity, and flow behavior during damage and microwave healing. Results indicate that ITAM exhibits enhanced microwave heating efficiency, reaching temperatures up to 109.4 °C, where the higher heating rate favors rapid crack repair in asphalt mixtures, and achieving a peak load recovery of 75.68 % in the first healing cycle, indicating substantial mechanical restoration. Freeze-thaw cycling significantly increased void connectivity and average void volume, whereas microwave heating partially restored the mesostructure by reducing connected voids, void volume, and flow channel length.