Unification and calibration of steel corrosion models based on long-term natural corrosion

The corrosion of steel bars in concrete has a significant influence on the durability deterioration of reinforced concrete structures. The purpose of this study is to investigate the prediction models of steel corrosion rate and the main influencing factors in the case of natural corrosion. The experimental results are obtained from the long-term natural corrosion induced by accelerated chloride erosion. Then, based on electrochemical corrosion kinetics, Ohm’s law, and potential field theory, numerical models for uniform and local corrosion are established respectively, and compared with the experimental results. The main parameters and influencing factors are deeply analyzed through the numerical models. The main conclusions are as follows: (1) The cell model based on Ohm’s law can be well adapted to uniform corrosion, especially when the resistivity of concrete is the controlling factor. (2) Among the parameters of electrode polarization, the cathode Tafel slope has the greatest influence on the numerical results, followed by the anode equilibrium potential. •It is attempted to unify uniform and localized corrosion models in modeling.•Key parameters in the corrosion model are calibrated based on a long-term test.•Effects of environmental factors on corrosion development are deeply analyzed.•Coupled analysis of oxygen concentration polarization at steel cathodic surface.