Corrosion-Induced Concrete Cracking, Steel-Concrete Bond Loss, and Mechanical Degradation of Steel Bars

Abstract

This study experimentally investigated corrosion-induced deterioration in reinforced concrete (RC) structures: concrete cover cracking, steel-concrete bond loss, and mechanical degradation of corroded steel bars. Pullout and RC beam specimens were prepared, subjected to accelerated corrosion in a wet sand bath, and tested under loading. A 3D laser scan was employed to measure the surface profile of corroded steel bars and determine the corrosion effect on the distribution of residual cross section area. The crack width on the concrete surface was sampled randomly and analyzed statistically. Corrosion reduced the bond strength between steel bars and concrete, particularly in the form of corrosion-induced number and width of cracks. Both the yield and ultimate strengths depended upon the critical cross sectional area of steel bars, whereas the elongation changed with the cross section distribution over the length of the steel bars. Corrosion also changed the distribution of the cross sectional area of steel bars. The crack width on the concrete surface can be well represented by a normal distribution regardless of corrosion levels.