Enhanced heating-healing performance of asphalt concrete modified with heterogenous microwave sensitive admixtures

Microwave heating technology has promising application potential in self-healing promotion of asphalt concretes. Addition of microwave absorbers or microwave reflecting admixtures to asphalt concretes improves the heating-healing efficiency under microwave radiation. Radiated by microwave, the asphalt concrete with heterogenous admixtures, namely both microwave absorbers and reflecting admixtures, is supposed to have higher healing ratio than the concrete with monotypic admixtures, due to the synergy interaction between the two heterogenous admixtures. In this research, an asphalt concrete incorporat-ing manganese dioxide powder as microwave absorber and steel fiber as microwave reflecting admixture was developed through an orthogonal design. Then the heating-healing capacity and road performances of the developed concrete were compared versus other concretes with same content of monotypic micro-wave sensitive admixtures. It is found that the healing ratio of the developed concrete exceeds other research subjects after 210 s of microwave heating. The content interaction of manganese dioxide powder and steel fiber has a statistically significant influence on the healing capacity. Besides, the monotypic addition of manganese dioxide powder also generates noteworthy enhancement in microwave heating-healing capacity and other road performances of the asphalt concrete. The results provide refer-ences to further increase the heating-healing capacity within limited admixture content. (c) 2021 Elsevier Ltd. All rights reserved.