Numerical Modelling of Pitting Corrosion in RC Structures

During its life expectancy, a RC structure is exposed to corrosion. This phenomenon attacks the reinforcement and lead to the creation of a third material that is rust, at the expense of steel. This corrosion material takes more volume than the lost volume of steel and generates internal stresses that lead to the deterioration of the steel-concrete interface and to the cracking of the concrete cover. The distribution of the rust around the reinforcement for a natural corrosion is non-uniform and irregular. This distribution is associated to corrosion “pits” that are localized and concentrated in the regions exposed to corrosion. To better study and understand the phenomenon of pitting corrosion, a 2D numerical model is adopted. This model associates the corrosion of the reinforcement to a single pit, located at the top of the rebar. A model that take into account the damaging of the concrete in compression and tension is used and an interface between the two materials that models a tangential and normal contact is adopted.