基于MD模拟的再生沥青混合料微观特性研究

Study on Micro-Characteristics of Recycled Asphalt Mixture Based on MD Simulation

摘要: 通过分子动力学方法(MD)选取植物油提取物油酸、亚油酸以及石油基提取物乙基四氢化萘三种再生剂成分，SiO₂、Al₂O₃、CaO、MgO四种氧化物，构建沥青粘聚模型以及沥青–集料界面模型，研究不同老化条件下，三种再生剂对沥青粘聚能以及沥青–集料界面粘附能的影响，并构建界面剪切试验模拟沥青–集料界面在剪切加载下的失效过程。结果表明：不同老化程度下4种氧化物集料与沥青之间的粘附能从大到小依次为：CaO > Al₂O₃ > MgO > SiO₂，碱性氧化物与沥青之间的粘附性大于酸性氧化物与沥青之间的粘附性；随着沥青老化程度加深，沥青质聚集程度加强，使其在受到剪切加载时表现出更高的抗剪切性能；相同条件下植物油在改善老化沥青混合料的粘附性能方面优于乙基四氢化萘。

Abstract: The molecular dynamics method (MD) was used to select the regenerating agent components of oleic acid, linoleic acid and petroleum-based extract ethyl tetrahydronaphthalene, and the four oxides of SiO₂, Al₂O₃, CaO and MgO, the effects of three kinds of reclaiming agents on the adhesion energy of asphalt and the adhesion energy of asphalt-aggregate interface under different aging conditions were studied, the interfacial shear test was constructed to simulate the failure process of asphalt-aggregate interface under shear loading. The results show that the adhesion energy between the four oxide aggregates and asphalt is CaO > Al₂O₃ > MgO > SiO₂ in order from large to small, the adhesion between basic oxide and asphalt is greater than that between acidic oxide and asphalt, and with the aging of asphalt, the degree of asphaltene aggregation increases, under the same conditions, vegetable oil is better than ethyl tetrahydronaphthalene in improv-ing the adhesion of aged asphalt mixture.