Predicting the initiation and propagation of corrosion in reinforced concrete structures

A detailed method is described for predicting carbonation and/or chloride induced corrosion in reinforced concrete structures. The initiation stage is modeled by tracing chloride and/or carbonation permeation into concrete. The effects of moisture and temperature on the spatial and temporal diffusion of these species are considered in the analysis. Corrosion is modeled by using the fundamentals of electrochemistry and the necessary polarization effects are considered in the analysis. The entire method is implemented in a finite element scheme and the accuracy and validity of the results are ascertained by comparing its results with available experimental data. Since the proposed formulation is twodimensional, it can model local variations in the concrete and other structural properties as well as in its exposure conditions, both spatially and temporally. It is significant that the corrosion amount and rate can be predicted along reinforcing bars and anodic and cathodic sites can be identified. A program of this type constitutes an extremely useful tool for assessing the long-term durability of structures in a given environment.