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

Reinforced concrete members with different degrees of corrosion coexist in a concrete structure and these members were connected in parallel in cathodic protection commonly. In order to consider the corrosion protection effect, possibility of malfunctions, and necessity of pretreatment, it is essential to understand current distribution into the rebars during application of cathodic protection. 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 a ICCP 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 cathodic protection for reinforced concrete in corrosive environments based on the experimental evidences.