Quantifying oxygen diffusion in bitumen films using molecular dynamics simulations


Bitumen in asphalt pavements reacts slowly with atmospheric oxygen, resulting in oxidative ageing. This oxidative reaction is strongly dependent on the physical diffusion of the oxygen into the bitumen. This study aims to use molecular dynamics (MD) simulation to investigate the oxygen diffusion into the bitumen film and analyse the effects of anti-ageing compounds (AACs) on the oxygen diffusion. The MD diffusion simulations using a Polymer Consistent Force Field (PCFF) were conducted on a bitumen-air bi-layer model at different temperatures. Fick's second law was used to calculate the diffusion coefficient of the oxygen in the bitumen film. It is found that the oxygen diffusion coefficients ranged from 6.67 × 10−10 to 7.45 × 10−11 m2/s for the unmodified and AAC-modified bitumens at the simulating temperatures of 25, 50 and 100 °C. Irganox acid and DLTDP (Dilauryl thiodipropionate):furfural showed two different anti-aging mechanisms, i.e., reducing the oxygen physical diffusion and controlling the chemical oxidative reaction. Reducing the oxygen diffusivity by constructing a network in the bitumen to retard oxygen diffusion and increase the transport path is an efficient way to slow down the bitumen aging without the antioxidant consumption. This work proposed a MD-based computational approach, contributing to 1) determination of the oxygen diffusion coefficient of the existing bitumen that is extremely challenging for the experimental measurement and 2) instruction of developing new antioxidant.

Publication DOI: https://doi.org/10.1016/j.conbuildmat.2022.127325
Divisions: College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Engineering Systems and Supply Chain Management
College of Engineering & Physical Sciences > Aston Institute of Urban Technology and the Environment (ASTUTE)
College of Engineering & Physical Sciences > Aston Institute of Materials Research (AIMR)
College of Engineering & Physical Sciences
College of Engineering & Physical Sciences > School of Infrastructure and Sustainable Engineering > Civil Engineering
Additional Information: © 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license 4.0 Funding Information: This work is part of a project that has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk?odowska-Curie grant agreement No 101030767.
Uncontrolled Keywords: Anti-ageing compounds,Bitumen,Molecular dynamics (MD),Oxygen,Physical diffusion,Civil and Structural Engineering,Building and Construction,Materials Science(all)
Publication ISSN: 0950-0618
Full Text Link:
Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
https://www.sci ... 0054?via%3Dihub (Publisher URL)
PURE Output Type: Article
Published Date: 2022-05-09
Published Online Date: 2022-03-31
Accepted Date: 2022-03-27
Authors: Gao, Yangming
Zhang, Yuqing (ORCID Profile 0000-0001-5825-0131)
Zhang, Chao
Liu, Xueyan
Jing, Ruxin



Version: Published Version

License: Creative Commons Attribution

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