Combined Impressed Current Cathodic Protection and FRCM Strengthening for Corrosion-Prone Concrete Structures

Abstract

This study introduces the use of the combined impressed current cathodic protection–structural strengthening (ICCP-SS) as a technique for repairing reinforced concrete structures that have been subjected to chloride-induced corrosion. The development of this technique is based on the combination of a carbon-fiber mesh (CF-MESH) and a polymer-modified cementitious matrix to produce a carbon-fiber-reinforced cementitious matrix (C-FRCM). First, the effects of different types and amounts of high molecular weight polymer and short chopped carbon fibers on the flexural and compressive strength, conductivity, and shear strength of a matrix with concrete substrate were investigated in order to find the optimum ingredients required for a high-performance cementitious matrix. Second, a shaped CF-MESH was bonded onto the surface of a concrete cube using the aforementioned optimized cementitious matrix. The impressed current cathodic protection (ICCP) technique was then applied to the specimens by using different current densities with the CF-MESH as the anode. During the protection period, the protection conditions of rebars subjected to ICCP were assessed by analyzing a variety of electrochemical parameters. Third, single shear tests were conducted, and the shear strengths and failure modes of the specimens were obtained and compared in order to evaluate the effects of the ICCP on shear stress transfer. The results show that the proposed technique based on the newly proposed C-FRCM composite is able to provide effective cathodic protection as well as shear stress transfer behavior to RC structures subjected to chloride-induced corrosion, leading to an improvement with respect to structural durability.