公路工程

采用粗粒化分子动力学(CGMD)模拟方法，系统地研究了阴离子乳化剂对乳化沥青形成与稳定性的影响，旨在为乳化沥青材料的优化设计提供理论依据。首先，基于Martini力场构建了水分子和阴离子乳化剂的粗粒化模型，验证了所用力场在描述该类体系中的可靠性与适用性。在此基础上，构建了乳液/沥青/乳液两相三层界面模型，以更真实地模拟乳化沥青的形成与稳定过程。研究发现，剪切速率和乳化温度对乳化沥青的形成具有显著影响。通过模拟不同剪切速率下的乳化过程，确定了0.000 5 ps^-1为最佳剪切速率，此时乳化沥青的界面张力达到最小值，有利于形成稳定的乳化沥青。在乳化温度方面，研究发现85～90℃(对应沥青加热温度为150℃)为理想范围，该温度下沥青与水的界面张力最小，乳化沥青的形成最为稳定。在乳化剂种类对稳定性的影响研究中，研究选取了4种常见的阴离子乳化剂，从界面张力、界面生成能、组分浓度分布与界面厚度及扩散系数4个方面综合评估其对乳化沥青稳定性的作用。结果表明，十二烷基磺酸钠(SDSN)乳化剂在降低界面张力、减少界面生成能、增加界面厚度和提高扩散系数方面表现最为出色，能显著提升乳化沥青的稳定性。

The influence of anionic emulsifiers on the formation and stability of emulsified asphalt was systematically studied using coarse-grained molecular dynamics(CGMD) simulation method, aiming to provide a theoretical basis for optimizing emulsified asphalt materials. Firstly, a coarsening model for water molecules and anionic emulsifiers was constructed based on the Martini force field, verifying the reliability and applicability of the applied force field in describing such systems. On this basis, a two-phase and three-layer interface model of lotion/asphalt/lotion was constructed to simulate the formation and stability of emulsified asphalt more realistically.Research has found that shear rate and emulsification temperature have a significant impact on the formation of emulsified asphalt. By simulating the emulsification process at different shear rates, the optimal shear rate was determined to be 0.000 5 ps^-1, at which the interfacial tension of emulsified asphalt reached its minimum value, which is conducive to the formation of stable emulsified asphalt.In terms of emulsification temperature, research has found that the ideal range is 85～90 ℃(corresponding to a heating temperature of 150 ℃ for asphalt). At this temperature, the interfacial tension between asphalt and water is the smallest, and the formation of emulsified asphalt is the most stable.In the study on the influence of emulsifier types on stability, four common anionic emulsifiers were selected, and their effects on the stability of emulsified asphalt were comprehensively evaluated from four aspects: interfacial tension, interfacial generation energy, component concentration distribution, interfacial thickness, and diffusion coefficient.The results showed that sodium dodecyl sulfonate(SDSN) emulsifier performed the best in reducing interfacial tension, decreasing interfacial generation energy, increasing interfacial thickness, and improving diffusion coefficient, significantly enhancing the stability of emulsified asphalt.