基于分子动力学模拟的沥青膜内氧气扩散行为研究  

Oxygen Diffusion Behavior in Asphalt Film Based on Molecular Dynamics Simulation

作　　者：张宇 李政 方珑 韩波 王伟成 毛自根 刘奇[5] 于斌[5] ZHANG Yu;LI Zheng;FANG Long;HAN Bo;WANG Weicheng;MAO Zigen;LIU Qi;YU Bin(Zhangjiagang Municipal Transportation Bureau,Zhangjiagang,Jiangsu 215638,China;China Design Group Co.,Ltd.,Nanjing,Jiangsu 210014,China;Lianyungang Municipal Transportation Bureau,Lianyungang,Jiangsu 222006,China;Anji County Transportation Investment and Development Group Co.,Ltd.,Huzhou,Zhejiang 313399,China;School of Transportation,Southeast University,Nanjing,Jiangsu 210018,China)

机构地区：[1]张家港市交通运输局,江苏张家港215638 [2]华设设计集团股份有限公司,江苏南京210014 [3]连云港市交通运输局,江苏连云港222006 [4]安吉县交通投资发展集团有限公司,浙江湖州313399 [5]东南大学交通学院,江苏南京210018

出　　处：《中外公路》2024年第4期115-126,共12页Journal of China & Foreign Highway

基　　金：江苏省交通运输科技项目(编号:2020Y19-1(1))。

摘　　要：沥青的老化是沥青路面使用过程中最受关注的问题之一。然而,沥青通常以薄膜的形式存在于混合料中。氧气扩散是影响沥青老化的重要因素,为了探究不同工况下氧气在沥青膜中的扩散行为,该研究建立了氧气‒沥青‒集料(OAA)模型,以模拟在实际情况下集料表面沥青膜状态。在不同时间、温度、氧气分子浓度和集料类型条件下,对OAA模型中氧气扩散和沥青组分迁移规律进行研究。通过计算分子的相对分子浓度、径向分布函数、均方位移和扩散系数,比较各因素对模型分子行为的影响,进一步分析各参数之间的联系。从分子模拟结果可知,氧气分子浓度随扩散时间的增加而增加,且集料与沥青界面处的氧气分子浓度明显上升。随着温度的升高,氧气向沥青膜内的扩散能力增强,氧气分子浓度随之线性增加。增加氧分子数量,沥青膜内的氧气相对分子浓度整体上升,CaCO_(3)集料更利于氧气向沥青膜内扩散。Asphalt aging is one of the most important concerns during the use of asphalt pavement.However,asphalt usually exists in the form of a film in the mixture.Oxygen diffusion is an important factor affecting asphalt aging.To investigate the oxygen diffusion behavior in asphalt film under different working conditions,an oxygen-asphalt-aggregate(OAA)model was developed in this study to simulate the state of the asphalt film on the aggregate surface under real conditions.Oxygen diffusion and asphalt component migration in the OAA model were investigated under different conditions of time,temperature,oxygen concentration,and aggregate type.The influence of each factor on the molecular behavior of the model was compared by calculating the relative concentration of molecules,radial distribution function,mean square displacement,and diffusion coefficient,and the connection between the parameters was further analyzed.From the molecular simulation results,it is clear that the oxygen concentration increases with the increase in diffusion time,and the oxygen concentration at the interface between aggregate and asphalt increases significantly.Higher temperature promotes the diffusion of oxygen into the asphalt film,and oxygen concentration varies nearly linearly with temperature.Increasing the number of oxygen molecules can make the relative concentration of oxygen molecules within the asphalt film increase overall,and the CaCO_(3) aggregate is more favorable for oxygen diffusion into the asphalt film.

关 键 词：道路材料 氧气扩散 沥青膜 分子动力学模拟 组分迁移 相对分子浓度 

分 类 号：U414[交通运输工程—道路与铁道工程]