摘要
为探寻水分对沥青自愈合的影响机理,采用分子动力学方法从分子角度对比分析常规沥青、水损沥青的自愈合过程,并通过宏观试验进行验证。首先,结合沥青体系能量变化,将愈合状态分为3个阶段:分子迁移低密度阶段、裂纹愈合及修复阶段、分子自由运动阶段;然后,运用径向分布函数和均方位移函数分析2种沥青在裂纹宽度、含水率、沥青组分的扩散机理和聚集状态,解释沥青的自愈合及水对沥青自愈合的影响机理;最后,进行宏观试验验证。结果表明:在裂缝自愈合过程中,水分将阻碍沥青分子间的作用力,削弱沥青体系能量,导致沥青扩散力降低,且含水量越多,扩散力下降越明显;裂缝减弱了沥青各组分的关联性,破坏了沥青质胶团和胶质过渡相的稳定性,且裂缝处的分子数目随着裂缝尺寸的增加而减少,促使沥青自愈合能力降低。采用分子动力学从分子角度解释沥青愈合机理的可靠性,有助于了解沥青分子在水损过程中结构形态和扩散行为的变化特征,为未来水损沥青自愈合的研究提供参考。
In order to explore the mechanism of water on self-healing of asphalt,the self-healing process of ordinary asphalt and water-damage asphalt was compared and analyzed from the molecular point of view by molecular dynamics,and was verified by macroscopic experiments.Firstly,the healing state was divided into three stages in combination with the energy change of the asphalt system:the low density stage of molecular migration,the stage of crack healing and repair,and the stage of free movement of molecules;Secondly,the radial distribution function and the mean square displacement function were used to analyze the diffusion mechanism and aggregation state of the two kinds of asphalt in crack width,moisture content and asphalt component,to explain the self-healing mechanism of asphalt and the influence mechanism of water on asphalt self-healing;Finally,macroscopic experiment verification was conducted.The results show that in the process of crack self-healing,water will hinder the intermolecular force of asphalt,weaken the energy of the asphalt system,resulting in a decrease in the diffusion force of the asphalt,and the more water content,the more obvious the decrease of diffusion force;Cracks weaken the correlation of asphalt components,destabilize asphaltene clusters and colloidal transition phases,and the number of molecules at the crack decreases as the crack size increases,which contributes to a reduction in self-healing ability.Using molecular dynamics to explain the fracture self-healing mechanism of water-damaged asphalt from the molecular scale is useful to understand the change characteristics of structural morphology and diffusion behavior of asphalt molecules during water loss,and provides a reference for the future research on self-healing of water-damaged asphalt.
作者
肖敏敏
董金勇
李春岩
杨礼明
朱兴一
XIAO Minmin;DONG Jinyong;LI Chunyan;YANG Liming;ZHU Xingyi(School of Urban Construction and Safety Engineering,Shanghai Institue of Technology,Shanghai 201418,China;Guangxi Communications Design Group Company Limited,Nanning,Guangxi 530000,China;Key Laboratory of Road and Traffic Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)
出处
《河北科技大学学报》
CAS
北大核心
2023年第1期46-57,共12页
Journal of Hebei University of Science and Technology
基金
国家自然科学基金(51922079)
广西省重点研发计划项目(桂科AB20159036)。
关键词
化学动力学
沥青水侵蚀
分子动力学
均方位移
径向分布
自愈合
Chemical kinetics
asphalt water damage
molecular dynamics
mean square displacement
radial distribution function
self healing
