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The chloride content is a critical factor influencing the corrosion of steel fibers in concrete. This study focused on the corrosion behaviors of steel fibers exposed to simulated concrete pore solutions with different chloride contents. The corrosion rates of the steel fibers were calculated based on the changes in the diameter and ultimate tensile load. The electrochemical parameters for the corrosion of the steel fibers were continuously monitored for 62 days. In addition, the surface micromorphologies of the corroded steel fibers were observed using scanning electron microscopy (SEM). The results showed that based on the change in the diameter, the corrosion rate of the steel fibers increased almost linearly when the NaCl content in the simulated solution increased from 2% to 5%. However, based on the variation of the ultimate tensile load, the corrosion ratio of the steel fibers increased linearly with the increase in the exposure time when the NaCl content was less than 3%, while it increased exponentially when the NaCl content exceeded 3%. According to the open circuit potential, Tafel polarization curves, and electrochemical impedance spectroscopy (EIS), the corrosion tendency and corrosion rates of the steel fibers exposed to the simulated solutions increased significantly when the NaCl content increased from 2% to 5%. Additionally, the corrosion damage on the surfaces of the steel fibers increased notably, and after 180 days of exposure to the simulated solution with 5% NaCl, the steel fiber was almost broken. These findings will help to understand the durability of SFRC in a chloride environment. [ABSTRACT FROM AUTHOR]

The corrosion of steel fibers is a direct cause of the deterioration of steel fiber-reinforced concrete in chloride environments. This study mainly investigated the corrosion behavior of steel fibers exposed to NaCl solutions with pH=7 , 10, 11, 12, and 13. The corrosion rate of the steel fibers was calculated according to the change of the diameter and ultimate tensile load. The electrochemical parameters of the steel fibers corrosion were continuously monitored. The morphology of the steel fibers affected by chloride attack was observed by scanning electron microscope (SEM). The results reveal that the corrosion rate of the steel fibers decreased as the pH of the NaCl solution increased from 7 to 13, and it was very small at pH≥12. According to the open circuit potential, corrosion potential, corrosion current density, and electrochemical impedance spectroscopy, the steel fibers exhibited a high corrosion tendency and corrosion rate when exposed to NaCl solutions with pH≤12. However, they exhibited low corrosion tendency in the chloride solution with pH=13. The surface roughness of the steel fibers exhibited only a slight increase after exposure to the NaCl solution with pH=13 for 180 days. [ABSTRACT FROM AUTHOR]