基于分子动力学聚合物改性沥青黏附性能研究

为了增强基质沥青与集料之间界面黏附性,选取PE、SBS、SBR、PU4种代表性聚合物对其进行改性,采用分子动力学模拟法对沥青-集料和沥青-水-集料模型进行不同工况模拟,并通过室内试验验证模拟结果。通过分析相对浓度分布曲线得到沥青极性组分的变化规律,研究不同温度下各改性沥青混合料黏附性并根据相对浓度参数对其机理进行分析,通过聚合物改性性能对比,得出其适用条件。结果表明:PE与沥青相溶性好,但PE改性沥青混合料水稳定性较差;SBS改性沥青能在温差较大的环境中保持较高的黏附性;SBR改性沥青低温条件下黏附性突出,且水稳定性优越,适用于低温多雨的地区;PU改性沥青综合性能较好,在高温多雨等气候条件复杂的环境中适用性较强。

In order to improve the adhesion between matrix asphalt and aggregate, four representative polymers, polyethylene(PE), SBS, SBR and polyurethane(PU), were selected to modify them, and molecular dynamics(MD) simulation method was used to simulate the models of asphalt-aggregate and asphalt-water-aggregate in different working conditions, and the simulation results were verified by laboratory tests. By analyzing the relative concentration distribution curve, the variation law of the polar components of asphalt was obtained. On this basis, the adhesion of each modified asphalt mixture at different temperatures was studied, and its mechanism was analyzed according to the relative concentration parameters. Finally, the applicable conditions were obtained by comparing the modified properties of the polymers. The results show that PE has good compatibility with asphalt, but the water stability of PE modified asphalt mixture is poor. SBS modified asphalt can maintain high adhesion in environments with large temperature difference. SBR modified asphalt has outstanding adhesion under low temperature conditions and superior water stability, which is suitable for low temperature and rainy areas. PU modified asphalt has good comprehensive performance and strong applicability in environments with complex climatic conditions such as high temperature and rain.