沥青胶结料自愈合行为的分子动力学模拟

Molecular Dynamic Simulation of Self-healing Behavior of Asphalt Binder

采用溶度参数作为沥青组分相容性的评价指标,验证了沥青各组分模型的合理性,通过四组分试验确定沥青组分比例后建立了沥青分子模型,并得到了沥青稳定构相.在沥青稳定构相中预设1nm的裂纹,采用分子动力学研究了沥青分子在不同温度条件下的密度、能量及均方位移变化规律.结果表明:在未达到平衡态时,沥青胶结料的密度、能量变化明显,沥青分子均方位移与时间呈非线性的关系,表明沥青分子的均方位移为非线性的次扩散过程;达到平衡态后,沥青胶结料密度和能量稳定,沥青分子扩散运动速度与时间线性相关性良好,分子扩散速度随温度提高而增加,表明采用分子模拟技术来模拟沥青分子自愈合行为是可行的.

Solubility parameter is used as an evaluation index for compatibility of asphalt components.The rationality of the model of each component of asphalt is verified.The asphalt molecular model was established after the proportion of asphalt component was determined by the four component test,and the asphalt stabilized structure was obtained.1 nm width of crack in the asphalt stable phase was preset,the variation of density,energy and mean square displacement of the asphalt molecules at different temperatures were studied by molecular dynamics simulation.The results show that before the equilibrium state,the density and energy change significantly,asphalt has sub-diffusive behavior,The mean square displacement of asphalt molecules has a nonlinear relationship with time,indicating that the mean square displacement of asphalt molecules is nonlinear secondary diffusion process,and when reaching equilibrium state,the energy and density stability,asphalt self-diffusion velocity and time have good linear correlation,the molecular diffusion rate increases with the increase of temperature,which shows that the simulation of asphalt molecular self-healing behavior is feasible using the research methods and ideas of molecular dynamic simulation.