Numerical Simulation of Corrosion-Induced Cracking of Concrete Considering Rust Penetration into Cracks

Evaluation of the concrete cracking induced by rebar corrosion is necessary for accurately clarifying the durability and predicting the service life of reinforced concrete (RC) structures. The fact that rust penetration into cracks might decrease corrosion expansion has been realized but not sufficiently investigated. In this paper, a numerical approach in terms of the mesoscopic structure of concrete is used to simulate the corrosion-induced concrete cracking, and the lattice network model to account for rust penetration into cracks is developed by assuming that the movement of rust is driven by moisture convection. The total rust amount is calculated based on Faraday’s law, and the rust expansion is transformed to a radial displacement boundary condition for both uniform and nonuniform conditions. Rust penetration is assumed to be a convection process governed by Darcy’s law. The proposed model is confirmed by comparing cracking pattern, corrosion pressure, surface crack width, mass ratio of penetrated rust to total rust ($\mathrm{\Delta }{W}_{\mathrm{pe}}/\mathrm{\Delta }{W}_{\mathrm{total}}$), and volume ratio of cracks occupied by rust to total cracks ($V_{\mathrm{rust}}^{\mathrm{crack}}/V_{\mathrm{crack}}^{\mathrm{total}}$) with available experimental and numerical results. It is found that the distribution and the amount of penetrated rust are closely related to the volume of cracks and the connection of crack networks. Besides, through sensitivity analysis of influencing factors for rust penetration, it is found that a higher dissolved degree of rust in moisture induces a higher $\mathrm{\Delta }{W}_{\mathrm{pe}}/\mathrm{\Delta }{W}_{\mathrm{total}}$, but it doesn’t influence $V_{\mathrm{rust}}^{\mathrm{crack}}/V_{\mathrm{crack}}^{\mathrm{total}}$. A larger relative water content at the concrete-steel interface will induce higher $\mathrm{\Delta }{W}_{\mathrm{pe}}/\mathrm{\Delta }{W}_{\mathrm{total}}$ and $V_{\mathrm{rust}}^{\mathrm{crack}}/V_{\mathrm{crack}}^{\mathrm{total}}$, while the initial relative water content in concrete has no significant difference on either $\mathrm{\Delta }{W}_{\mathrm{pe}}/\mathrm{\Delta }{W}_{\mathrm{total}}$ or $V_{\mathrm{rust}}^{\mathrm{crack}}/V_{\mathrm{crack}}^{\mathrm{total}}$.