bond behavior between high-strength recycled aggregate concrete and uhssb using beam test

This study investigates the bond–slip behavior between high-strength recycled coarse aggregate concrete (rac) and ultra-high-strength steel bar with spiral groove (uhssb). twenty-four beam tests were carried out to consider the effects of recycled coarse aggregate (rca) replacement ratio, concrete cover thickness, stirrup ratio, concrete strength, addition of steel fiber and presence of anti-corrosion coating. the influences of different parameters on failure mode, bond–slip curve and bond strength are discussed. the reinforcement is pulled out in all specimens before it yields. the reduction of the rca replacement ratio, the increase of the concrete cover thickness or stirrup ratio, and the addition of steel fiber are capable of preventing the concrete from splitting and reducing the crack width. the rca replacement ratio has little effect on bond strength which decreases by no more than 13%. increasing the concrete cover thickness and increasing the stirrup ratio in a certain range can significantly increase the bond strength. however, mixing steel fiber has little effect on the bond strength. furthermore, the bond strength of rac is positively correlated with f’c1/2, which is similar to that of nac. the anti-corrosion coating significantly reduces the bond strength. the bond–slip model is proposed based on the fitting of test results. the results of this research can provide a reference for the engineering application of high-strength rac and uhssb.