Feasibility of the use of galvanic couples to develop corrosion sensors for reinforced concrete structures

Abstract

This investigation is a first step in the development of a simple sensor to be embedded in concrete structures to measure the corrosion rate of reinforcement steel (rebars) based on the principle of galvanic couple. To that end, suitability of using galvanic couple current monitoring as a method of sensing rebar corrosion was studied. Three different galvanic couples (carbon steel/stainless steel, carbon steel/copper, and carbon steel/titanium), as well as simple rebars, were embedded in mortar samples. The objective was to find out if there exists a correlation between the current of the galvanic couples and the real corrosion rate of the rebars in a wide range of environmental conditions. The measurement of the galvanic current showed the importance of the anodic/cathodic area ratio. It was found that when this ratio was 1:7 a relationship between the galvanic current of the carbon steel/copper couple and the corrosion current of the rebars could be established. Among the three galvanic couples proposed, the carbon steel/copper one seems to be the most promising with which to build a sensor.