Estimation of Corrosion Risk Using Concrete Electrical Resistivity Model

Abstract

The purpose of this study is to develop a prediction method for the durability of reinforced concrete against salt attacks for any mix proportions and environmental conditions. To accomplish this, we investigate the effects of concrete composition and water content on resistivity and then model resistivity for any aggregate volume fractions using a modification of McCarter's resistivity model of concrete. We separately model the resistivity of cement paste, taking into account the effective amount of liquid water in the capillary and gel pores and the structure of C-S-H. This is incorporated into the proposed resistivity model. As a result, it is possible to predict the risk of corrosion due to salt attacks for a range of concrete compositions and environmental factors. In particular, it has become possible to model the corrosion resisting effect of using blast furnace slag as a mineral admixture. Further, it has become possible to determine the corrosion risk in consideration of the length of the drying periods between times of wetting.