Electrochemical characterization of Solid Ag/AgCl reference electrode with different electrolytes for corrosion monitoring of steel in concrete

Abstract

Solid Ag/AgCl reference electrodes (RE) with different electrolytes were assembled and characterized in concrete. The performances have been studied with respect to known RE. And the corrosion states of steel have been investigated with respect to embedded and external REs by different electrochemical techniques. Results revealed that half-cell potential of 0.1, 1 and 4.18M AgCl RE was 20mV, -30.5mV and -54.6mV, respectively. In addition, 4.18M AgCl RE exhibited the minimum potential drift, the smallest temperature coefficient value and the best reversibility. These corrosion parameters such as rebar potential, corrosion current density (Icorr) and charge transfer resistance (Rct) obtained for steel with respect to these embedded AgCl REs could clearly differentiate the active condition of steel from the passive condition. Besides, Icorr and Rct obtained for steel with respect to external SCE were usually 2 or 3 times larger than these embedded AgCl REs. In such cases embedded AgCl REs could accurately investigate the corrosion rate of steel in concrete. Moreover, the 4.18M AgCl RE was recommended to monitor the corrosion condition of steel in concrete structure.