Influences of Concrete Resistivity on Corrosion Rate of Steel Bar in Concrete

Abstract

Corrosion rate of steel bar in concrete plays an important role in load bearing-capacity evaluation, maintenance decision and residual life prediction of existing RC structures. A macro cell corrosion model was developed to investigate the influences of concrete resistivity on corrosion rate of steel bar in concrete based on the electrochemical principle and the Bulter-Volmer equation. Analysis results show that concrete resistivity has significant effect on corrosion rate of steel bar in concrete if the limit current density is relative large and the steel corrosion is under control of ion transportation. With the increase of relative humidity, the limit current density decreases obviously and the steel corrosion is influenced by both oxygen diffusion and concrete resistivity. However, if the concrete resistivity is relative small, steel corrosion will be under control of oxygen diffusion.