Effects of Corrosion Pits on Mechanical Properties of Corroded Steel Bars

In order to investigate the effects of corrosion pits on the mechanical properties of corroded steel bars, three-dimensional geometric models of steel bars with different corrosion degrees were obtained by using three-dimensional laser scanning technique, and the geometric shapes and parameters of corrosion pits were analyzed. It was found that corrosion pit can be given with a hyperbola; therefore, the effects of geometric parameters for a hyperbola on mechanical properties of corroded steel bars were analyzed and discussed by use of a proposed numerical analysis model, which was validated by tensile test results of steel bars with machined corrosion pits. In the model, the corrosion pits were assumed to be axially symmetric and a real stress-strain relationship of uncorroded steel bars was used. It was found that the reduction of the nominal strength of corroded steel bars is mainly caused by the variation of the cross-sectional area along the longitudinal axis, while the degradation of the ultimate elongation and shortening of the yield plateau mostly results from the stress concentration at the corrosion pit.