Yao Hui, Liu Junfu, Xu Mei, Bick Andreas, Xu Qing, Zhang Jinxi
Beijing Key Laboratory of Traffic Engineering, Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, No.100, Pingleyuan, Chaoyang, Beijing, 100124, China.
Scienomics SARL, 16 rue de l'Arcade, 75008, Paris, France.
Sci Rep. 2021 May 10;11(1):9890. doi: 10.1038/s41598-021-89339-5.
Asphalt binder is the main material for road pavement and building construction. It is a complex mixture composed of a large number of hydrocarbons with different molecular weights. The study of asphalt binders and asphalt concretes from a molecular perspective is an important means to understand the intricate properties of asphalt. Molecular dynamics simulation is based on Newton's law and predicts the microscopic performance of materials by calculating the intra- and intermolecular interactions. The asphalt binder can be divided into four components: saturates, aromatics, resins, and asphaltenes (SARA). A new molecular model of asphalt was proposed and verified in this study. Eight molecules selected from the literature were used to represent the four components of asphalt. The AMBER Cornell Extension Force Field was applied in this study to model building and the calculation of properties. The density of the asphalt model was calculated and compared with experimental results for validity verifications. The results show that the purposed model can be used to calculate the microscopic properties of the asphalt binder because the density of the model is close to the real value in the field. Besides, the proportions of different molecules in the model were adjusted to predict the relationship between the asphalt binder density and the hydrocarbon ratios and heteroatom contents of the molecular model. Moreover, the glass transition temperature of the asphalt binder model is predicted by the simulation of the heating process. The range of the glass transition temperature is determined by calculating the relationship between specific volume and temperature, and the calculated range is close to the experimental value.
沥青结合料是道路路面和建筑施工的主要材料。它是一种由大量不同分子量的碳氢化合物组成的复杂混合物。从分子角度研究沥青结合料和沥青混凝土是理解沥青复杂性能的重要手段。分子动力学模拟基于牛顿定律，通过计算分子内和分子间的相互作用来预测材料的微观性能。沥青结合料可分为四个组分：饱和烃、芳烃、树脂和沥青质（SARA）。本研究提出并验证了一种新的沥青分子模型。从文献中选取的八个分子用于代表沥青的四个组分。本研究应用AMBER康奈尔扩展力场进行模型构建和性能计算。计算了沥青模型的密度，并与实验结果进行比较以进行有效性验证。结果表明，所提出的模型可用于计算沥青结合料的微观性能，因为该模型的密度与实际值接近。此外，调整模型中不同分子的比例以预测沥青结合料密度与分子模型中烃比例和杂原子含量之间的关系。此外，通过加热过程的模拟预测了沥青结合料模型的玻璃化转变温度。通过计算比容与温度之间的关系确定玻璃化转变温度范围，计算出的范围与实验值接近。
