Quantifying oxygen diffusion in bitumen films using molecular dynamics simulations

Yangming Gao, Yuqing Zhang*, Chao Zhang, Xueyan Liu, Ruxin Jing

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


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.

Original languageEnglish
Article number127325
JournalConstruction and Building Materials
Early online date31 Mar 2022
Publication statusPublished - 9 May 2022

Bibliographical note

© 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.


  • Anti-ageing compounds
  • Bitumen
  • Molecular dynamics (MD)
  • Oxygen
  • Physical diffusion


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