Study on the bond behavior of corroded steel bars embedded in concrete under the coupled effect of reciprocating loads and chloride ion erosion

Abstract

This work presented an experimental investigation on bond behavior of corroded steel bars embedded in concrete under the action of three different levels of reciprocating loads (25%, 45% and 65% of ultimate load) and sustained chloride attack using 51 RC beam specimens with dimensions of 100 mm × 150 mm × 550 mm. In the test, the steel is corroded by the method of energized accelerated corrosion (theoretical corrosion ratio of steel is set as 2%, 4% and 6%). Test results show that the effect of reciprocating load will cause the bond strength between uncorroded steel bars and concrete to decrease in the chloride environment, but the effect is not significant. Under the coupled effect of reciprocating loads and energized accelerated corrosion, when the corrosion ratio of longitudinal reinforcement is constant, as the increase of the reciprocating load level, the bond strength between the steel bar and concrete of the specimen decreases. When the theoretical corrosion ratio of steel bars is small, the bond strength between steel bars and concrete gradually increases with the increase of the corrosion ratio; as the corrosion ratio of steel bars further increases, the bond strength shows a downward trend. The theoretical corrosion ratio of steel bars reaches a peak of about 2%. In this paper, the mathematical model of bond strength-slip has been proposed. This work provided an important theoretical basis for correctly assessing the durability of buildings or structures subjected to reciprocating loads in coastal areas.