Quantitative Interpretation of Half-Cell Potential Measurements in Concrete Structures

The interpretation of half-cell potential measurements in reinforced concrete structures can be a major challenge for civil engineers. The main reason for this is that half-cell potential mapping provides information to predict the probability of corrosion in concrete, but it does not give clear insight on the rate and the nature of corrosion. Although for general uniform corrosion, half-cell data can provide valuable information about the probability of corrosion. In the case of localized corrosion, the predictions of half-cell measurements can be misleading. The main objective of the present work is to provide practicing engineers a tool that they can use to better interpret the results of half-cell potential measurements. This tool quantitatively relates the potential readings on the surface of the concrete to the rate of probable localized reinforcement corrosion through concrete resistivity, cover thickness, and temperature, allowing the engineers to gain supplementary information from half-cell tests. Experimental comparisons presented in this paper demonstrate the potential benefits of the proposed approach when typical half-cell measurements may not be able to predict the localized corrosion mechanism.