分子模拟研究不同条件下沥青自愈合规律

The Law of Asphalt Self-healing with Different Conditions on Molecular Dynamics Simulations

采用沥青四组分的方法来确定沥青模型,并通过比较沥青模型的密度和实际沥青的密度,来验证沥青模型的合理性.采用合理的沥青大分子模型建立沥青裂缝模型,并模拟不同条件下沥青自愈合的试验过程.在裂缝模型中加入定量的水分子,用以模拟不同含水率的环境.根据实际的老化沥青中各组分的含量变化,建立老化沥青分子模型,模拟沥青老化对沥青愈合的影响.结果表明:愈合模型在30 ps之后开始稳定;水分子的加入会使沥青自愈过程的扩散系数降低,当含水量大于3%时,水对沥青扩散的影响逐渐稳定;选取Z轴方向上的水分子浓度曲线,当含水率高于3%时,水分子浓度的峰值集中在分子的愈合裂缝处.

The asphalt four-component method was used to establish the asphalt model,and the rationality of the asphalt model was verified by comparing the density of the model with the actual asphalt. A reasonable asphalt macromolecular model was used to establish the asphalt crack model,and the experimental process of asphalt selfhealing with different conditions was simulated. Adding quantitative water molecules to the fracture model was carried out to simulate different moisture content environments. According to the actual content change of each component in aged asphalt,the molecular model of aged asphalt was established to simulate the effect of asphalt aging on asphalt healing. The result shows as follows. The healing model begins to stabilize after 30 ps. The addition of water molecules will reduce the diffusion coefficient of asphalt self-healing process. When the water content is more than 3%,the effect of water on asphalt diffusion is gradually stabilized. The water molecule concentration curve in the Z-axis direction was selected. When the water content is higher than 3%,the peak of the water molecule concentration is concentrated at the healing crack of the molecule.