Evaluation of Self-Healing Performance of Asphalt Concrete for Macrocracks via Microwave Heating

This study aims to evaluate the effect of microwave radiation on the self-healing performance of asphalt mixture. Fracture-healing-fracture test was conducted via semicircular bending (SCB) test and microwave heating. The ratio of tensile strength before and after healing was defined as healing index (HI), which was used to evaluate the self-healing properties of asphalt mixture. The self-healing performance was investigated by considering heating time, microwave power, and temperature. Surface temperature of two kinds of specimens showed a good binary linear regression relationship with heating time and microwave power. The increase of heating time and microwave power could promote the self-healing behavior in a certain range, which was mainly related to the temperature of the asphalt mixture after microwave heating. The two kinds of specimens had good mechanical strength recovery when the surface temperature reached about 80°C.