Study on Current Distribution into Reinforced Concrete Members with Different Degrees of Corrosion in a Cathodic Protection Circuit

Reinforced concrete (RC) members with different degrees of corrosion coexist in a concrete structure and these members were connected in parallel in cathodic protection (CP) commonly. To consider the corrosion protection effect, possibility of malfunctions, and necessity of pretreatment, it is essential to understand the current distribution into the rebars during the application of CP. In this study, each rebar in four mortar specimens was exposed under a controlled condition to simulate four different corrosion stages, and the current distribution was clarified by conducting a current supplying test with a parallel circuit of the four mortar specimens in an impressed current CP system. Furthermore, by taking into account the solution resistance from each anode to the rebar including the cover mortar resistance and polarization resistance of the rebar, the main determinants of the current distribution were presumed, followed by a discussion of the appropriate circuit separation. The achievements of this study are meaningful for considering highly reliable and reasonable CP for RC in corrosive environments based on the experimental evidence.