Shear performance of interface between ultra-high performance concrete and normal concrete treated with ribs

In order to investigate the interfacial bonding performance between ultra-high performance concrete (UHPC) and normal concrete (NC) treated with ribs, shear push-test are conducted to examine the influence of rib size, rib space, and rib number on the failure mode and shear strength of UHPC-NC interface. Furthermore, a finite element mode is developed to study the effect of different parameters on the shear bearing capacity of the interface. Finally, a calculation method that can be utilized to predict the shear strength of UHPC-NC interface treated with ribs is proposed. The results show that the shear bearing capacity of the interface can be significantly improved by ribbed treatment, and the shear bearing capacity gradually increases with the increase of the number of ribs. The specimens with rib width of 10 mm are prone to rib shear failure, while the specimens with rib width of 15 mm and 20 mm are mainly subjected to NC shear failure. In addition, for the specimens with rib width of 15 mm and 20 mm, increasing the rib height and NC strength can improve the shear bearing capacity of the interface. Finally, the proposed calculation method for predicting the shear capacity of the UHPC-NC interface treated with ribs demonstrates good accuracy. The average ratio between the calculated value and the experimental value is 1.03 and the standard deviation is 0.13.