Electrochemical Characterization of a Solid Embeddable Ag/AgCl Reference Electrode for Corrosion Monitoring in Reinforced Concrete

In this study, a new solid embeddable Ag/AgCl reference electrode (RE) was electrochemically investigated for corrosion monitoring in reinforced concrete. The electrode was fabricated by applying the cement mortar as the bottom layer, and the polymer gel as electrolyte. Several electrochemical methods were applied. The experiments were carried out in simulated concrete solutions and concrete. Furthermore, an exposure period over 1 year was used to evaluate the stability of the electrodes embedded in concrete. It has been found that the electrode potential was not obviously affected by the chloride concentration, but affected by the pH value of solution. The Ag/AgCl RE had uniformity in concrete environments. The reversibility of Ag/AgCl RE in all solutions is only within +/- 4 mV. Besides, potentiodynamic tests revealed that the Ag/AgCl RE had a high exchange current density, which was advantageous when using Ag/AgCl RE to conduct resistance tests. Galvanostatic application of 0.2 mu A/cm(2) caused little variation of potential with time (similar to 30 mV in several days), indicating the presence of a finite polarization resistance. As a result, the new solid Ag/AgCl RE was suitable as a sensor electrode for concrete structures. (C) The Electrochemical Society of Japan, All rights reserved.