Experimental study on the bond strength of different geometries of corroded and uncorroded reinforcement bars

This study develops empirical models for the prediction of the bond strength of uncorroded and corroded reinforcement bars. The effects of hooked reinforcement on the bar’s development length when covered fully and partially are examined. An accelerated corrosion method is used to corrode the reinforcement bars embedded in concrete specimens. Pull-out tests are performed to investigate the ultimate bond strength of the concrete specimens. The effects of two different geometries of reinforcement bars are discussed by considering two different concrete strength levels and concrete cover depths. It is found that partly covered hooked reinforcement bars increase the radial stress on the concrete surface and reduce the bond strength. Increases in the bond strength due to the increased roughness of the steel bar caused by the confined corrosion products are less for hooked bars. The results reveal that the developed models show good relationships with the experimentally computed test results.