Time-Dependent Model for Evaluating Corrosion Potential and Electrical Resistivity of Reinforced Concrete

Abstract

The main work presented in this paper is to propose prediction models for estimating electrical resistivity of concrete and corrosion potential of steel in reinforced concrete. The prediction models for electrical resistivity of concrete (r) and corrosion potential of steel (E_corr) incorporated hydration degree (α_Hyd (t)), pozzolanic reaction degree (α_Poz (t)), porosity (P_Cap (t)) and chloride content ([CL^-]). Predicted results were verified with results of experimental measurement. An experimental program was run for 1 year with various concrete mix proportions. According to the results, corrosion resistance of concrete increased with time as the degree of hydration increased. Further, the introduction of fly ash offered a good corrosion resistance, which also increased with time. Lastly, the existence of chloride ions in the concrete weakened passive film on steel surface, by the fact that its presence eased the movement of ions in the concrete and increased the risk of corrosion.