Study on the influence of ribs on the bonding performance between ultra-high performance concrete and normal concrete

This study investigated the bonding performance of the interface treated by ribs between Ultra-High Performance Concrete (UHPC) and Normal Concrete (NC) through double shear tests and finite element analysis. Besides, according to existing research results, the calculation methods for the shear capacity of the interface between UHPC and NC were discussed. The results show that specimens with a rib width of less than 20 mm were predominantly susceptible to rib shear failure, whereas those with a rib width exceeding 20 mm primarily exhibited NC fractures failure. The impact of rib height and rib spacing on the interface failure mode was complex and should be assessed based on the rib width. When the rib width was less than 20 mm, with an increase in rib spacing, the shear bearing capacity of the interface remained nearly constant. Nevertheless, when the rib width was 30 mm, the bearing capacity gradually decreased with an increase in rib spacing. Additionally, the bearing capacity initially increased and then decreased with an increase in rib height for specimens with a rib width exceeding 10 mm. The current calculation methods neglected the bearing capacity provided by the ribs, resulting in significant discrepancies between calculated results and experimental values.