Indices for self-healing performance assessments based on molecular dynamics simulation of asphalt binders

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• 作者：Daquan Sun ; Tianban Lin ; Xingyi Zhu ; ^{zhuxingyi66@aliyun.com" class="auth_mail" title="E-mail the corresponding author} ; Yang Tian ; Fuliang Liu
• 关键词：Asphalt ; Self-healing ; Molecular dynamics ; Activation energy
• 刊名：Computational Materials Science
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：114
• 期：Complete
• 页码：86-93
• 全文大小：4132 K

文摘

Understanding the self-healing mechanism and efficiently evaluating healing potential of asphalt materials is a crucial topic, which is especially necessary for a precise prediction of fatigue life. Most existing laboratory test methods to evaluate healing are empirical or phenomenological in nature, leading to an underestimation of fatigue life significantly. Self-healing processes are inherently of hierarchical, multiscale character. Therefore, researches of healing mechanisms may effectively require discrete atomistic treatments. In this paper, molecular dynamics (MD) simulation was used as a tool to examine the hypothesis of healing mechanism and evaluate the self-healing capability of neat and SBS modified asphalt binders. Densities and glass transition temperatures of neat and SBS modified asphalt binders were figured out based on the MD simulation results. An artificial crack was created in MD model to simulate the diffusion of molecules across a crack interface. Three indices calculated from MD simulation results were put forward to evaluate the self-healing capability of asphalt binders, including diffusion coefficient, activation energy, and pre-exponential factor. Finally, the values of these three indices obtained from MD results were compared with the values derived from fatigue-rest-fatigue test, to assess the reliability of above indices as self-healing performance indicators.