Dual responsive microwave heating-healing system in asphalt concrete incorporating coal gangue and functional aggregate

The development of multifunctional asphalt concrete with a high heating-healing capability has emerged as a crucial focus in achieving pavement maintenance and sustainable infrastructure. However, striking a balance between achieving a high healing efficiency without compromising mechanical strengths and preventing aggregation of functional additives has presented a challenge. To address this, a novel concept of a dual responsive microwave heating-healing system in asphalt concrete is proposed, which incorporates coal gangue (CG) and functional aggregates. By incorporating functional aggregates, a robust and functional skeleton structure can be established within the asphalt concrete, facilitating the healing of microcracks at the interfaces between aggregates and asphalt. Simultaneously, the inclusion of CG in the asphalt mixture facilitates the healing of microcracks within the mastic. Remarkably, the incorporation of dual functional additives in the optimized asphalt concrete results in only a marginal decrease of 2% in maximum tensile strength and 1.5% in crack resistance compared to plain porous asphalt samples. Furthermore, the optimized asphalt samples exhibit healing index values exceeding 60% after undergoing five damage-healing cycles. To develop heating-healing asphalt concrete, it is recommended to utilize 100% CG in combination with functional aggregates. This comprehensive approach takes into account the valuable reuse of CG powder, as well as the associated environmental and economic benefits. This study introduces a promising strategy for achieving a highly efficient heating-healing capability in asphalt concrete, presenting significant potential for its practical applications in the field of sustainable pavement engineering.