Molecular Dynamics Simulation of Reinforcing Steel Corrosion when Subjected to Both Chloride Attack and Mechanical Loading

Abstract

This paper describes the corrosion process of reinforcing steel under both chloride attack and mechanical loading. Molecular dynamics simulation is adopted to investigate the evolution process of passive film and oxidation process of reinforcement. The mean square displacement and self-diffusion coefficient of O₂ under different conditions are also obtained based on molecular dynamics simulation. It is shown that the present of chlorides can increase the energy of Fe atoms on the surface of Fe₃O₄ substrate, leading Fe atoms to separate from Fe₃O₄ easily and to get more chance to react with oxygen atoms. The interaction of chloride attack and mechanical loading can aggravate the damage of passive film on the surface of reinforcement and result in an increase of oxidation depth of Fe matrix. The coupled effects of chloride and static loading can accelerate the diffusion of O₂ to the iron matrix, thus increasing the oxidation reaction between the iron matrix and O₂.