Analytical modeling of bond stress at steel-concrete interface due to corrosion

An analytical model that describes the deterioration of bond strength, due to corrosion of steel reinforcement, at the steel-concrete interface in a reinforced concrete is developed. Concrete is assumed as a thick-walled cylinder subjected to internal pressure exerted from the growth of corrosion products on the concrete at the steel-concrete interface. The concrete in the inner cylinder is considered as an anisotropic material with stiffness degradation factor as an exponential function, while at the outer cylinder, the concrete is treated as an isotropic material. A frictional model is used to combine the action of confining pressure resulted from radial pressure produced by principal bar ribs on surrounding concrete, and corrosion pressure resulted from the expansion of corrosion products. The results of the proposed model are validated with experimental results by several researchers and a good agreement was noted; this shows that the derived analytical model was able to satisfactory [sic] predict the reduction of bond strength between steel and concrete.