ABSTRACT
This paper examined the impacts of environmental humidity, concrete properties, chloride ion concentration, cover thickness and other factors on half-cell potential measurement results. The paper then proposes a quantitative determination standard on the critical corrosion potential of concrete reinforcement in practical engineering inspection through electrochemical acceleration corrosion experiments on reinforced concrete specimens. Research results indicated that (1) the slope change of a low frequency curve in electrochemical impedance spectroscopy (EIS) reflected the development of steel bar corrosion in concrete. As the slope decreased to 0, the steel bar gradually reached critical corrosion, and the corresponding critical corrosion time followed the Gumbel distribution. (2) Under practical humidity conditions, the variation of concrete reinforcement corrosion potential correlated with concrete internal Cl− concentration using an e exponential function relationship. While the Cl−concentration was greater than 0.2%, the potential variation would not increase any more after reaching 55mV. (3) With changes of cover thickness, the critical corrosion potential of concrete reinforcement exhibited a linear variation at a gradient of -1.64mV/mm.
