Deterioration pattern of the axial compressive properties of steel-reinforced concrete columns owing to chloride salt erosion

The study of the durability of steel-reinforced concrete (SRC) columns under the influence of coastal moisture–heat coupling has grown in prominence. In this study, electrochemical corrosion and axial pressure loading tests were performed on 10 SRC columns. These tests studied the effects of varying corrosion rates and CL⁻concentration on the axial pressure performance of the SRC columns when conducted in an energized medium, and the results revealed the modes of failure and the degradation laws. The ultimate bearing capacity and stiffness of SRC columns increasingly deteriorate with increasing corrosion rate; the ductility index also deteriorates to certain extent. When the corrosion rate exceeds 20 %, each index parameter of the test column deteriorates. During the axial compression test, the concentration of CL⁻in the energized medium primarily increases the growth rate of strain in the elastic-plastic phase during the middle and late loading stages. This leads to further deterioration of the SRC columns in multiple ways, such as cracking of the protective layer of concrete, weakening of the material properties, and damage to the cross-section. Based on this experimental study, the modeling of SRC columns under chloride salt erosion was performed using a new finite-element method. In addition, the Mander constrained concrete model and the Biondini concrete cracking model were used to theoretically derive the ultimate bearing capacity of the corroded SRC column.