Self-Healing Analyses of Asphalt Cracks under Changing Temperature Conditions through Molecular Dynamics

Asphalt pavement has the potential ability of micro-crack self-healing during the rest periods, and temperature is the main influencing factor. In order to reveal the effect of changing temperature on the self-healing performance of asphalt micro-cracks by microwave heating, the crack models of asphalt binder consisting of three and four components were constructed and the molecular dynamics (MD) method was used to analyze the diffusion performance of the asphalt crack under the conditions of constant temperature and changing temperature. The mean square displacement was analyzed by the density change curve and the diffusion coefficient was obtained through determining the number of frames when the crack was self-healed. The results show that under the same temperature parameter simulation conditions, both the three and four component asphalt crack models healing efficiency of asphalt micro-cracks was the best under the constant high temperature of 373 K, followed by the changing temperature from 303 K to 373 K, and healing efficiency under the constant low temperature of 303 K was the lowest. The diffusion coefficient in the changing temperature is close to the diffusion coefficient at a constant high temperature, which is reasonably close to the self-healing efficiency of both. The improved simulation method can better describe the diffusion ability of asphalt cracks under the effect of temperature change, and provide a theoretical basis for microwave heating to promote the asphalt crack self-healing.