Application of Ag/AgCl Sensor for Chloride Monitoring of Mortar under Dry-Wet Cycles

Abstract

An Ag/AgCl electrode used as a corrosion sensor in a reinforced concrete structure isconsidered as having good application prospect. However, its performance under complexconditions, such as dry-wet cycle condition, is not affirmed. In the current study, the performanceof Ag/AgCl as chloride selective electrode in mortar exposed to dry-wet cycle condition wasinvestigated. A simple Ag/AgCl electrode was prepared and fabricated by electrochemicalanodization. These Ag/AgCl electrodes were embedded into a mortar specimen with temperaturesensors, humidity sensors and anode ladder monitoring system (ALS). After 28 d curing time, theupper surface of mortar specimen was wetted (with 5% NaCl solution) and dried regularly. Theobtained results indicate that Ag/AgCl electrode responds to the ingress of chloride ion, sensitively.The chloride ion concentration variation can be reflected by the potential trend. Furthermore, thebalance potential of Ag/AgCl electrodes is influenced by dry-wet cycles. Compared with ALS, itdemonstrates that Ag/AgCl electrodes are more sensitive to chloride. The research provides the keyelement for the specific application of Ag/AgCl electrode for corrosion monitoring in the future.