New non-destructive method for linear polarisation resistance corrosion rate measurement

Corrosion of steel reinforcement is one of the most common causes of end service life in reinforced concrete structures. Corrosion is initiated and propagates unseen beneath the concrete cover and it is difficult to evaluate the severity of the problem. The most promising electrochemical method is the Linear Polarisation Resistance method which can provide a direct evaluation of the instantaneous rate of corrosion. The main drawback to this technique is that it requires a localized breakout of the concrete cover to provide an electrical connection to the steel reinforcement. This article describes an adaptation of the LPR method and the four-point Wenner resistivity method to give an assessment of the rate of steel corrosion without the requirement for a direct connection to the reinforcement. The measurements have been performed in cooperation with Construction and Infrastructure Group in University of Liverpool.