Chloride ion sensor for concrete structures
Chloride ions are one of the major reasons of the deterioration of concrete constructions. The threshold amount of chloride ions inside concrete initiate rapid corrosion of steel rebar. In-situ monitoring of the chloride ions in concrete is, therefore, inevitable for sustainable constructions. Electrochemical sensors are the most appropriate sensors, for monitoring of chloride ions, due to their reliability, easiness and speed. Most of the reported electrochemical sensors use potentiometry where the half-cell potential of a silver/silver chloride (Ag/AgCl) electrode is measured with respect to a reference electrode at equilibrium. The drift due to the change in reference potential over time limits this approach for long-term usage in concrete. This drift can be counteracted by differential electrochemical measurement such as chronopotentiometry, where a current stimulus at the Ag/AgCl electrode results in a potential gradient. This potential gradient is a function of the chloride ion concentration and is independent of the reference potential. This talk will explore the possibilities of long-term and in-situ monitoring of chloride ions inside concrete.