Tensile behaviour of pitting corroded steel bars: Laboratory investigation and probabilistic-based analysis

Abstract

Localised corrosion in steel bars has been a long-standing issue in the durability of reinforced concrete structures, but a comprehensive scheme for the analysis of pitting corroded steel bars, especially with respect to the deformation capacity, is not currently available. In this study, the morphological characteristics of 27 pitting steel bars were captured using a 3D scanner. The measured data were used to establish the probability distribution model of the cross-sectional areas of the corroded bars. Uniaxial tensile tests were conducted, and the evolving deformation field of the corroded bars was recorded through Digital Image Correlation (DIC). Based on the 3D reconstructed model and DIC results, an analytical method for evaluating the mechanical properties of pitting steel bars was developed and validated. The results show that the two-component Gaussian mixture distribution model outperforms conventional unimodal distribution models. Comparison of the analytical results with experimental data demonstrates that the proposed procedure is capable of predicting not only the ultimate strength but also the gauge length-dependent ultimate strain of corroded bars. Additionally, there exists a strengthening effect in the ultimate stress at the critical sections and this effect should not be ignored for accurate predictions.