Cathodic Protection of Reinforcing Steel in Concrete Using Conductive-Polymer System

Abstract

This paper presents experimental results from a novel study to investigate the feasibility of using a dual sacrificial anode cathodic protection (SACP) system that combined corrosion protection with strengthening. A conductive polymer was used to bond the zinc plates to the concrete surface to form the SACP system, while a single unidirectional carbon fiber-reinforced polymer (CFRP) sheet was bonded to the zinc surface to provide strengthening. However, the aim was not to evaluate strengthening, but to determine if the CFRP interfered with the performance of the SACP system. Four concrete prisms, two of which were strengthened, were tested. The specimens were all placed in a high humidity environment, and their potential and galvanic current measurements were carried out over the entire 295-day exposure period. It was found that the SACP system performed adequately, although there was an apparent decrease in the protective current due to passivation of the zinc plate. Although the potential results from both SACP systems studied (bare Zn plate versus Zn+CFRP ply) were different, the current delivery was similar, indicating little interference between the Zn plate and the carbon fiber ply attached on top of this plate.