Study on the bond behavior of steel bars embedded in concrete under the long-term coupling of repeated loads and chloride ion erosion

Twenty-seven reinforced concrete beam specimens were cast to study the bond properties between steel bars and concrete under the coupling of chloride ion erosion and repeated load (0, 0.25, 0.45, and 0.65 of ultimate load) for 210 days. The bond strength and slip of steel bars embedded in concrete were measured by the flexural bond test. Based on the test results, the higher the level of repeated load alone, the lower the bond strength. The bond strength of beam specimens under the coupling of repeated load and chloride ion erosion is lower than that under repeated load alone or chloride ion erosion alone. The bond strength decreases gradually when the corrosion ratio exceeds 1.5%. The slip between steel bars and concrete decreases with the increase of repeated load level under the coupling of chloride ion erosion and repeated load when splitting failure occurs. Based on the test results, the bond strength-slip constitutive relationship was proposed.