Meso-scale phase field modelling of reinforced concrete structures subjected to corrosion of multiple reinforcements

Corrosion-induced concrete cover cracking is one of major deterioration mechanisms for reinforced concrete (RC) structures. Concrete cracking caused by corrosion of multiple reinforcements at the meso-scale involves complex toughening mechanism, stress redistribution and crack interaction. It brings significant challenge to accurately predicting the cover cracking which, in most cases, represents a critical stage of serviceability. This paper aims to develop a meso-scale phase filed model for concrete cover cracking induced by corrosion of multiple reinforcements. Concrete is treated as a three-phase heterogeneous material, consisting of aggregates, mortar and interfacial transition zones (ITZ). The developed method is implemented into ABAQUS explicit regime through an in-house VUEL subroutine. The crack patterns and crack width development of concrete induced by corrosion are obtained. The model is also verified against experimental results on the crack width development and crack patterns. Further, a parametric study is carried out to investigate the effects of reinforcement spacing, cover thickness, ITZ fracture properties on concrete cover cracking. Some toughening mechanisms including crack deflection, aggregate/mortar bridging and crack bifurcation in concrete have been captured in the model. ITZ fracture properties significantly affects the crack pattern of concrete cover. The developed method enables high fidelity numerical models with up to tens of millions of degrees of freedom (DOFs), and the completed failure processes of concrete cover are well predicted