Analysis of the interface bond property between the concrete and steel bar under textile reinforced concrete confinement

Abstract Determining the interface bond property between the concrete and steel bar under textile-reinforced concrete (TRC) confinement has been one of the important problems to solve for evaluating the TRC-strengthened effectiveness. This study adopted a research method combining experimental studies and theoretical analysis to discuss the mechanisms by which the steel bar shape, concrete strength and TRC confinement affect the interface bond property based on center pull-out tests. Furthermore, the interface damage variable and the damage-slip equation were presented to analyze the interface damage process. The research results showed that TRC confinement can improve the interface bond property of the specimens using a deformed bar and change its failure mode from splitting to splitting-pull out. The concrete strength had a significant impact on the interface bond property and the ultimate interface bond strength, but the influence degree is greatly reduced after TRC confinement. Moreover, the secant slope between the points on the bond-slip curve and the origin of the coordinate as the damage variable can be used to describe the degree of interface damage. The damage analysis results show a good consistency with the test results and bond mechanism analysis.