Self-Healing Properties of Graphene Oxide–Modified Asphalt Based on Molecular Dynamics

Abstract

To elucidate the influence mechanism of graphene oxide (GO) on the self-healing properties of modified asphalt, molecular dynamics simulations were employed to investigate the self-healing characteristics of matrix asphalt and polyphosphoric acid (PPA)–modified asphalt with GO incorporation. Models of matrix asphalt, GO-modified asphalt, and GO/PPA composite–modified asphalt were constructed, and their rationality was validated using radial distribution function (RDF), density, and solubility parameters. Subsequently, dynamic calculations were performed on the self-healing models of matrix asphalt, GO-modified asphalt, and GO/PPA composite–modified asphalt with 1 nm (10 Å) microcracks. A comparative analysis of the variations in density, structural phase, mean-square displacement, and diffusion coefficients during the self-healing processes of the three types of asphalt was conducted. Furthermore, the statistical analysis of the movement characteristics of asphalt molecules with cracks in different external environments was conducted. The results revealed that the ranking order of self-healing performance of the three asphalt types during crack diffusion healing was as follows: GO/PPA composite–modified asphalt > matrix asphalt > GO-modified asphalt. Furthermore, the external environment also significantly influenced the self-healing properties of asphalt. The microcracks in matrix asphalt, GO-modified asphalt, and GO/PPA composite–modified asphalt were repaired more quickly with an increase in temperature. The self-healing process of asphalt was inhibited by water in the cracks, and the effect became more prominent as the water content increased. GO-modified asphalt’s self-healing properties are better understood by this research, which also serves as a reference for similar studies.