Interfacial characteristics between bitumen and corrosion products on steel slag surface from molecular scale

Xu, Haiqin, Zou, Yingxue, Airey, Gordon, Wang, Haopeng ORCID: 0000-0002-5008-7322, Zhang, Hanyu, Wu, Shaopeng, Chen, Anqi, Xie, Jun and Liang, Yang (2024) Interfacial characteristics between bitumen and corrosion products on steel slag surface from molecular scale. Construction and Building Materials, 417. p. 135324.

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Abstract

Corrosion commonly happened on the surface of steel slag during the weathering and accumulation process, whose products would form weak points and affect the interface between bitumen and steel slag. To clear its characteristics in the atomic scales, the interface between bitumen and corrosion products was investigated by molecular dynamics (MD) simulations. Firstly, bitumen model, corrosion products model and bitumen-corrosion products systems were constructed. Different simulated temperatures were applied on the systems to reach equilibrium with NVT (constant number of atoms, volume, and temperature) ensemble. The interaction effect in the interface were evaluated by geometric adsorption index, interaction energy, adhesion work and surface free energy. Diffusion coefficient and relative concentration were used to evaluate the diffusion and aggregation. Finally, the pull-out test was conducted on the equilibrium models to determine the debonding behaviors at the interface. The results show that the interaction effect in Bitumen-FeO system was the strongest while that in Bitumen-FeOOH system was the weakest, which can be proved by surface free energy and debonding behaviors. The temperature changing would affect van der Waals energy but had no obvious association with coulombic energy. The adhesion between bitumen and corrosion products was contributed by non-bond interaction energy which consisted of van der Waals interaction for Fe3O4, Fe2O3 and FeOOH, and van der Waals and electrostatic interaction for FeO. The most severe aggregation of bitumen occurred in Bitumen-FeO system, which was more likely caused by electrostatic interaction. Furthermore, the change of velocity and thickness led to the failure transformation from cohesion to adhesion. The strong interaction in Bitumen-FeO system increase the possibility of cohesion failure in the debonding process.

Item Type:	Article
Divisions:	Faculty of Science and Engineering > School of Engineering
Depositing User:	Symplectic Admin
Date Deposited:	27 Feb 2024 08:22
Last Modified:	28 Feb 2024 23:03
DOI:	10.1016/j.conbuildmat.2024.135324
Related URLs:	Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3178906