Corrosion monitoring of reinforcement steel using galvanostatically induced potential transients

Investigation and results on a dynamic measurement technique to qualitatively evaluate the status of corrosion of reinforcement steel are presented. The sensing method is based on the measurement of the time constant of the relaxation of the current-induced polarization potential. This time constant corresponds to the polarization resistance and, therefore, the amount of corrosion. The polarization resistance decreases from 655 to 10 k cm2 and from 670 to 300 k cm2 for pore solutions with and without chloride ions, respectively. This is a dynamic measurement to determine the status of corrosion, i.e., active or passive corrosion where a long-term stable reference electrode is not required. Furthermore, a priori knowledge of the actual surface area of the steel is not required