Electrochemical techniques for corrosion assessment

This paper reviews the results of ?ve di?erent electrochemical techniques which have been investigated for use in evaluating corrosion rates of steel re- inforcement in concrete structures. Linear polarization resistance, harmonic analy- sis, AC impedance and galvanostatic pulse transient analysis are all techniques which were found to give consistent rates of corrosion. Electrochemical-noise measure- ments were found to be less suitable for this application. Electrical equivalent- circuit models are derived for corroding and passive steel bars in concrete, and these are used to interpret and understand the results obtained from each technique. The practical use of each technique is discussed, and optimum measurement parameters for practical application have been derived from the experimental studies.