Assessment of reinforcement corrosion by means of galvanostatic pulse technique

The galvanostatic pulse technique was introduced for field application in 1988 to overcome problems with interpretation of corrosion risk assessment based on half-cell potential measurements of the reinforcement. Since then development work has been conducted in order to allow quantitative evaluation of the corrosion rate. FORCE Institute, DK, and the Institute for Materials Chemistry and Corrosion, ETH, CH, have independently developed devices based on galvanostatic pulse technique. These devices which differ in design were used in the comparative test on a post-tensioned bridge in Switzerland. Results of this test show that the two devices give the same specific concrete resistivity and the same specific polarization resistance on active rebars when the size of the counter electrode is taken into consideration in the evaluation. On passive rebars the results differ, the device without guard ring shows a deviation of the current signal.