Effect of concrete pore saturation on cathodic protection of steel-reinforced concrete bridges

A two-dimensional finite difference simulation was developed to study the b ehavior of cathodic protection (CP) systems for actively corroding reinforc ed concrete structural elements. The potential and current distributions in a simplified rectangular geometry were determined. Input parameters were b ased upon available experimental data. The model indicated that: (1) enviro nmental conditions at the structure, particularly the degree to which concr ete pores are saturated with water, greatly affect system performance; (2) in drier conditions, bulk resistivity of the concrete limits the current, w hile in moist conditions, oxygen becomes depleted and water reduction comme nces; and (3) large variations can occur in the interfacial potential diffe rence along the steel-concrete interface.