Combined effect of chloride and sulfate ions on the corrosion behavior of Q355B steel in simulated concrete pore solution

Abstract

By integrating electrochemical testing and microscopic characterization, this paper investigates the corrosion behavior of Cl- and SO42- on Q355B steel in high pH simulated concrete pore solutions. Experiments showed that when Cl- and SO42- were brought into the simulated concrete pore solution system, the corrosion exhibited inhibition then promotion as the SO42- concentration increased. The occurrence of this phenomenon can be attributed to the competitive adsorption of Cl- and SO42-, which initially inhibits corrosion, followed by synergistic penetration that promotes corrosion. Moreover, SO42- have a negligible impact on the formation of pitting but encourages the growth of already-formed pits. Surface roughness exhibited a decrease with the increase of SO42- concentration.