Research on self-healing properties of crumb rubber modified asphalt based on molecular dynamics simulation
Self-healing models of base asphalt and crumb rubber modified asphalt were built using the asphalt 12 molecular model and the styrene-butadiene rubber(SBR)molecular model,and molecular dynamics simulations were used to investigate the motion rule and the diffusion behaviour of asphalt molecules during asphalt self-healing process at different temperatures.The self-healing ability of the as-phalt molecules and the crumb modified modified asphalt model was evaluated in terms of density,mean square displacement,cohesive ener-gy density and relative solubility.The results of the research showed that the time of density of the self-healing model of crumb rubber modified asphalt reached stability earlier than that of the self-healing model of base asphalt.The self-healing diffusion coefficients of the two models increased with increasing temperature.The overall diffusion coefficient of the crumb rubber modified asphalt is larger under all temperature conditions,indicating that the addition of crumb rubber can significantly increase the diffusion coefficient of asphalt,and the self-healing performance is better than that of the base asphalt.From the change of relative concentration,the self-healing of asphalt can be divided into three stages of diffusion,contact,and mutual fusion,and the time of relative concentration value of the model of crumb rubber modified asphalt tends to 1 earlier than the model of base asphalt self-healing.This calculation result has consistency with the density and mean square displacement,which all indicate that the self-healing effect of crumb rubber modified asphalt is better than that of the base asphalt.
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