Current Efficiency in Accelerated Corrosion Testing of Concrete

The suitability of accelerated corrosion testing using an impressed current, especially the accuracy of Faraday's law to estimate the mass loss, was assessed in this paper. A variety of tests were performed in concrete and solution with different chloride concentrations and impressed current to assess the accuracy of using Faraday's law to estimate the mass loss of corroded steel. The results indicate that Faraday's law does not predict the mass loss accurately for all conditions, and the percentage error increases with decreasing chloride concentration in the system. It is hypothesized that Faraday's law cannot be used to estimate the mass loss because competing reactions take place at the anode, especially at low chloride concentrations and high current. Under unfavorable conditions, only a part of the impressed current oxidizes the anode to create corrosion products while the remaining current is consumed in competing reactions.