A novel model for corrosion-induced cracking and spalling in reinforced concrete structures: I - theoretical framework and solution techniques

In this work, a new damage model for cohesive fracture is presented. The concept of damage driving mechanism is introduced, from which the damage evolution law is derived. Special attention is paid to non pure mode-I and mode-II fracture modes, such as mixed-mode fracture and mode-II fracture under compression. Conversely to the previous traction-based damage model (Alfaiate et al. 2023), where the damage variables are derived from uniaxial tensile and shear relationships, the damage variables are now obtained explicitly from reference traction-jump displacement relationships, leading to an integration of fracture mechanics concepts with a damage mechanics approach. In this way, it is possible to explicitly control the dissipation of energy. The model is aimed at the simulation of the behaviour of reinforced concrete structures under corrosion. Corrosion affects i) cracking, which is modelled with a discrete crack approach, ii) bond-slip degradation between steel and concrete, iii) the reduction of the sane cross section of the reinforcement steel and iv) spalling of the concrete cover. In this work some illustrative examples of the performance of the model are shown. In part II, examples of reinforced concrete structures with and without corrosion are presented.