Determination of critical anodic and cathodic areas in corrosion processes of steel reinforcement in concrete

Recently it has been demonstrated that the position and size of anode and cathode areas strongly influences crack pattern and corrosion rate . To investigate this influence the expression for maximum entropy production, deduced from irreversible thermodynamics, is formulated. The entropy is produced by dissipative processes, which are in this special case the flow of ions through the electrolyte, the anodic and cathodic polarization and the oxygen diffusion process. Through several numerical examples, in which the size and position of anodic and cathodic surfaces are varied, it is demonstrated that the maximum entropy production leads to the maximum corrosion-induced damage.