On-site determination of corrosion rate in reinforced concrete structures by use of galvanostatic pulses

Galvanostatically induced potential transients can be used to determine the corrosion rate and double layer capacitance (C) of steel in reinforced con crete structures, provided that the steel surface area involved in the meas urements is known. An approximate capacitance value, based on previous expe rience, can also be used to determine polarisation resistance even if the a rea of the working electrode (WE) is unknown, as in the case of measurement s on life-size structures using small counter electrodes. In the case of sm all specimens, in which direct determination of C is possible, the reliabil ity of the pulse technique is comparable to that of other widely accepted e lectrochemical procedures. In the case of life-size structures, its reliabi lity is lower due to the need to use estimated values of C. The results indicate that neither the magnitude of the perturbing pulse nor the lack of uniformity of the polarisation on the WE are factors that sign ificantly prejudice application of the current pulse technique in on-site m easurements on large reinforced concrete structures. (C) 2001 Elsevier Scie nce Ltd. All rights reserved.