Nonexponential Transients Resulting from Application of the Interruption Technique to Assess Corrosion Rate of Steel in Concrete

A numerical method was developed to model the voltage response after a direct current (DC) interruption through an equivalent circuit representing a steel/concrete system. Based on computer simulation and experimental observations, the paper discusses the applicability of classical procedures of analysis of the voltage decay curves in order to assess the corrosion status of reinforcing steel. It is shown that the accuracy of these determinations may be strongly dependent on the nonexponential behavior of the response, and it may therefore be significantly affected by the duration of the current pulse applied and the portion of the decay curve used in the analysis. Apparently, more elaborate methods of analyzing voltage decay curves are necessary.