Risk of galvanic corrosion induced by CFRP strengthening in reinforced concrete

Carbon fiber reinforced plastics (CFRP) used for the strengthening of reinforced concrete structures damaged by steel corrosion can promote galvanic coupling phenomena. The risk of macrocouple generated by conductive carbon fibers on corroding steel was investigated. Reinforcing bars subjected to pitting corrosion in chloride contaminated concrete were coupled with CFRP laminate embedded in chloride-free concrete and with externally bonded CFRP laminates or sheets. The CFRP laminate embedded in concrete generated a remarkable macrocouple current. When the CFRP were externally bonded to surface of the concrete, consequences of galvanic coupling were negligible, even at temperatures higher than 40°C. The macrocouple current greatly increased when a layer of mortar was applied to coat the composite material.