ANALYSIS OF THE SELF-HEALING PROCESS OF ASPHALT AND ITS INFLUENCING FACTORS

Molecular dynamics was used in this study to understand the self -healing behavior and mechanism of asphalt. Density, solubility, and mean square displacement parameters were analyzed to confirm the validity of the matrix asphalt model. Molecular simulation software was used to develop a microscopic matrix asphalt self-healing model at the nanoscale. Cracking width of asphalt microcracks was represented by setting different vacuum layer thicknesses as the asphalt self-healing model. Density and diffusion coefficient of the self-healing model were obtained by running the molecular software to understand the entire process of asphalt healing. The self-healing mechanism of the matrix asphalt was analyzed. Results showed that the entire self-healing process of asphalt could be clearly divided into four stages, namely, external environment energy endowment, model end healing, asphalt microcrack healing, and self-healing model self-diffusion stages. Molecules of each component in the asphalt self-healing process diffuse and move mutually under constant temperature conditions. The diffusion coefficient of saturated components and polar aromatic was higher than that of asphaltenes and aromatic components.