Self-healing behavior of asphalt system based on molecular dynamics simulation

Haida Liang , Guannan Li , Songtao Lv , Jie Gao , Karol Kowalski , Jan Valentin , Alessio Alexiadis

Abstract

The molecular model of asphalt binder was established by means of molecular dynamics (MD). The MD model was validated with respect of density, glass transition temperature, viscosity and solubility parameters. An interface system was created by inserting a vacuum pad of 50 Å between 2 groups of asphalt binders to study the self-healing behavior of the asphalt binder, e.g. internal volume, diffusion rate of each component and energy variation of the model. The molecular diffusion of aged asphalt binder, SBS modified asphalt binder, and virgin asphalt binder are studied. The results show that the ‘‘compression” of asphalt binder volume and the ‘‘stretching” of the asphalt binder molecules is responsible for the disappearance of vacuum micro-cracks inside the asphalt binder. When the model volume is ‘‘compressed”, the volume of the asphalt model decreases until the micro-cracks in the asphalt binder disappear completely. The molecular volume of asphalt decreases greatly at the beginning of the MD simulation, and then becomes stable. The length of asphalt model increases in the OZ direction, while the length of the OX and OY directions decreases, indicating that asphalt ‘‘stretces” during the selfhealing process. During the self-healing process, the diffusion coefficient of asphaltene molecule is the lowest, while the diffusion coefficient of the saturates is the highest at 360 K, aromatics and resins are close to the average value 6.227 10�4 cm2 /s in the MD model. Self-healing is mainly based on the Van der Waals forces between non-bonded molecules. The aging of asphalt molecules reduces the diffusion rate of the asphalt model, and the SBS additive indirectly enhances the diffusion rate of asphalt.
Author Haida Liang - Nottingham Trent University
Haida Liang,,
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, Guannan Li - [Harbin Institute of Technology]
Guannan Li,,
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, Songtao Lv - [Changsha University of Science and Technology]
Songtao Lv,,
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, Jie Gao - [Chongqing Jiaotong University]
Jie Gao,,
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, Karol Kowalski (FCE / IRB)
Karol Kowalski,,
- The Institute of Roads and Bridges
, Jan Valentin - [Ceske vysoke uceni technicke v Praze]
Jan Valentin,,
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, Alessio Alexiadis - [University of Birmingham]
Alessio Alexiadis,,
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Journal seriesConstruction and Building Materials, ISSN 0950-0618, e-ISSN 1879-0526
Issue year2020
Vol254
Article number119225
Keywords in EnglishAsphalt, Self-healing behavior, Molecular dynamics simulation, Diffusion coefficient
ASJC Classification2205 Civil and Structural Engineering; 2215 Building and Construction; 2500 General Materials Science
DOIDOI:10.1016/j.conbuildmat.2020.119225
Languageen angielski
Score (nominal)140
Score sourcejournalList
ScoreMinisterial score = 140.0, 03-09-2020, ArticleFromJournal
Publication indicators Scopus Citations = 0; Scopus SNIP (Source Normalised Impact per Paper): 2018 = 2.369; WoS Impact Factor: 2018 = 4.046 (2) - 2018=4.685 (5)
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