Modeling Mechanical Behavior of Reinforced Concrete due to Corrosion of Steel Bar

Expansion of a steel bar due to corrosion causes tensile stresses in concrete around the reinforcing bar and may induce cracking through the concrete cover. The purpose of the present study is to explore realistic mechanical properties of the corrosion layer, including the pressure-free corrosion strain and the stiffness of the corrosion layer. The corrosion products that penetrate into the pores and cracks around a steel bar have been considered in the calculation of expansive pressure due to steel corrosion. A realistic relationship between the expansive pressure and the average strain of the corrosion product layer has been derived and the representative stiffness of the corrosion layer was also determined. A concept of free-expansion (pressure-free) strain of the corrosion product layer was newly introduced to describe the relationship between the expansive pressure and the corrosion layer strain. The comparisons were made between the theory and test data on the surface strains of the concrete cover according to the corrosion amount for various concrete strengths and cover thicknesses. The proposed theory reasonably agrees with experimental data and may be a good base for the realistic durability analysis/design of concrete structures. [PUBLICATION ABSTRACT]