Mathematical modeling of corrosion of reinforcing steel in submerged concrete in sea water

The aim of this work was to obtain the electrode potential profile of steel in a reinforced cylindrical concrete structure which was immersed in sea water, as a function of surface concrete chloride concentration and pH, taking into account Green Rust (GR1, Fe-4(OH)(8)Cl) formation as a corrosion product. The proposed model is based on a bi-directional chloride flux through the concrete thickness. It allows one to predict the chloride concentration profile along metal/concrete interface, and also when the critical concentration (necessary to cause passive film breakdown) has been reached and the time necessary to (at fixed concrete thickness and chloride effective diffusion coefficient). With these values, the redox potential may be estimated. Through a series of field data, the capability of the model was tested and yielded good correlation.