为了研究老化对环氧沥青(EA)粘结剂性能的影响,采用分子动力学(MD)模拟研究了环氧沥青的氧化老化效应。构建了包括饱和分、沥青质、胶质、芳香分和环氧树脂在内的未老化环氧沥青的分子模型,通过在原始沥青组分中引入酮类和亚砜类官能团建立了老化环氧沥青分子模型。比较老化前后的内聚能密度(CED)和自由体积分数(FFV),发现氧化老化导致环氧沥青分子间结合强度增大,自由体积减小。径向分布函数(RDF)和回转半径(Rg)的结果表明老化削弱了沥青质的聚集和环氧树脂对周围沥青分子的包裹能力。最后,采用均方位移(MSD)对氧化老化前后环氧沥青分子的扩散行为进行评价,结果显示氧化老化会减缓环氧沥青分子的扩散。这些模拟结果共同揭示了环氧沥青各组分在老化过程中的作用机制,为后续环氧沥青材料抗老化性能的实验室研究提供了一定的理论依据。
In order to study the effect of aging on the performance of epoxy asphalt (EA) binder,the oxidative aging effect of epoxy asphalt was investigated using molecular dynamics (MD) simulations.A molecular model of unaged epoxy asphalt including saturated fraction,asphaltene,gum,aromatic fraction and epoxy resin was constructed,and a molecular model of aged epoxy asphalt was established by introducing ketone and sulfoxide functional groups into the original asphalt fraction.Comparing the cohesive energy density (CED) and free fraction volume (FFV) before and after aging,it was found that oxidative aging led to an increase in the intermolecular bonding strength and a decrease in the free volume of the epoxy asphalt.The results of radial distribution function (RDF) and radius of gyration (Rg) indicated that aging weakened the aggregation of asphaltenes and the ability of the epoxy resin to encapsulate the surrounding asphalt molecules.Finally,mean square displacement (MSD) was used to evaluate the diffusion behavior of epoxy asphalt molecules before and after oxidative aging,and the results showed that oxidative aging slowed down the diffusion of epoxy asphalt molecules.Together,these simulation results revealed the mechanism of action of each component of epoxy asphalt in the aging process,which provided a certain theoretical basis for the subsequent research on the anti-aging performance of epoxy asphalt materials.
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基金资助
国家自然科学基金(52078241);江苏省青年基金项目(BK20210058);江苏省青年基金项目(BK20220219)
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