Monitoring chloride-induced corrosion of carbon steel tendons in concrete using a multi-electrode system

To monitor real-time the occurrence of localized corrosion in reinforced concrete structures a novel multi-reference electrode is proposed, consisting of a Series of metallic wires placed head-to-tail able to measure the corrosion potential of a carbon steel tendon or a rebar network. Available embeddable or portable reference electrodes give the local potential of the rebar; with the new system, a single potential reading can give the corrosion condition of a wide area. Copper, nickel and stainless steel were tested as candidate metallic materials: laboratory tests allow verifying their stability in alkaline condition. The ability to detect and locale corrosion was demonstrated on mortar and grout specimens, cast to simulate chloride-induced corrosion on post-tensioned tendons. (C) 2015 Elsevier Ltd. All rights reserved.