Meso-scale mixed-mode fracture modelling of reinforced concrete structures subjected to non-uniform corrosion

Corrosion-induced concrete cracking is a significant problem affecting the durability of reinforced concrete structures. Considerable research has been carried out in addressing this problem but few have considered the cracking process of concrete as a mixed-mode fracture and the concrete as a multi-phase material. This paper develops a meso-scale mixed-mode fracture model for the cracking of concrete structures under non-uniform corrosion of reinforcement. Concrete is treated as a three-phase heterogeneous material, consisting of aggregates, mortar and interfaces. An example is worked out to demonstrate the application of the derived model and is then partially verified against previously published experimental results. In agreement with experimental results, the new model reproduces the observation that microcracks tend to form first at the interfaces before they connect to generate a discrete crack. Toughening mechanisms, e.g., microcrack shielding, crack deflection, aggregate bridging and crack overlap, have been captured in the model. Further, effects of aggregate randomness on the crack width development of concrete structures, differences between uniform and non-uniform corrosion and a comprehensive parametric study have been investigated and presented.