Numerical model for corrosion rate of steel reinforcement in cracked reinforced concrete structure

The presence of cracks in concrete will accelerate the corrosion of steel reinforcement causing the performance degradation of reinforced concrete (RC) structure. Based on the electrochemical principle, a numerical model of macro-cell corrosion has been developed to predict the corrosion rate of steel reinforcement in cracked RC members. In this model, the areas of the separate anode and cathode are established by the crack width, and the electric resistivity of concrete material is modified by considering the effects of water-binder ratio and other factors. When the corrosion rate of steel reinforcement is taken as the mean value of the corrosion current density of anode zone, the corrosion rate can then be numerically solved from the proposed model with given boundary conditions. Test data from the 2-year laboratory experiments of authors and literature has been collected to verify the proposed model. The comparisons between the test and prediction results show that the proposed model is of capability to predict the corrosion rate with a good accuracy. Finally, the parametric studies show that the crack width, water/cement ratio, chloride concentration, thickness of concrete cover, and relative humidity has significant influences on the corrosion rate of reinforcement in cracked RC structure.