Relationship between electrochemical noise and corrosion rate of steel in salt contaminated concrete

Abstract

Electrochemical noise has been assessed from a number of different forms of reinforced concrete specimen by monitoring fluctuations in the corrosion potential of the embedded steel to microvolt resolution. The standard deviation (S_n) of the potential noise signal has been related to corrosion rates obtained. independently by linear polarisation measurements applied to small electrodes and by measurement of galvanic currents flowing within artificially created macrocells in larger specimens. Under well controlled conditions it was possible to demonstrate a reproducible correlation between S_n and corrosion rate and this provided a basis for estimation of local corrosion rates of steel reinforcing bars embedded in a large concrete slab. It is considered, however, that practical limitations of the method will restrict its scope for application to in situ corrosion monitoring of real structures.