The Application of FEM to Cathodic Corrosion Protection of Steel Reinforcement in Concrete

Abstract

Cathodic protection has been applied widely to steel reinforcement in concrete. However, it is generally very difficult to establish optimal corrosion protection for such steel and to precisely evaluate the corrosion protection effect. We evaluate the effects of various factors on the distribution of the protective current, and summarize the information for optimal corrosion protection. For this purpose we refined a numerical analysis technique using FEM to optimize the cathodic protection of the reinforcing steel in concrete. We have constructed a precise method to calculate the potential and current distribution in the concrete, which can account for ion migration, ion diffusion, and the polarization phenomena involving the anode and reinforcing steel. We have estimated the effect of anode shape on corrosion protection. The polarization properties derived from electrochemical measurements were used as boundary conditions for the FEM calculation. This calculation technique incorporates polarization behavior and variations of ion concentration due to ionic migration and diffusion, giving a precise estimate of the actual corrosion protection effect of a system. We have shown the typical effect of various factors on the current distribution for corrosion protection systems in concrete, as given by FEM.