Microwave heating-induced self-healing of steel slag asphalt concrete: 3D mesoscopic simulations and experimental insights

Microwave heating (MH) is a sophisticated technique for asphalt facility maintenance, effectively enhancing the self-healing (S-H) of cracks in asphalt concrete (AC). This study selects steel slag (SS) to enhance MH performance in AC, and proposes an innovative theoretical framework that integrates numerical simulations, theoretical analyses, and experimental research to address the challenge of uneven MH. A randomized aggregate placement algorithm was employed to simulate the mesostructure of AC, enabling the precise optimization of MH technology and the creation of an energy-based performance evaluation method that addresses the limitations of traditional surface temperature-based assessments. Key findings demonstrate that the standing wave field, determined by the cavity frequency, governs the internal temperature distribution. Optimization of SS content and distribution significantly improves S-H performance, with the AS60 mixture achieving a healing efficiency of 79.62% at 2.45 GHz. These findings provide robust theoretical support and practical guidelines for MH applications.

Graphical abstract