Review of the Interfacial Bonding Properties between Ultrahigh-Performance Concrete and Normal Concrete

As a high-quality building material exhibiting excellent toughness and durability, ultrahigh-performance concrete (UHPC) is increasingly being used in the construction industry as reinforcement. During reinforcement of existing structures with UHPC, their interface weakest part structure. Interface bonding ensures operation two types materials together. However, studies rarely report UHPC–normal (NC) interface. Herein, test methods mechanisms are summarized. Subsequently, differences among relevant design codes investigated by comparing different theoretical formulas. Important influencing factors method, namely, roughness, fiber type content, agent moisture strength, cementitious curing conditions, freeze–thaw cycles, chloride ions, also considered. Further, enhancement mechanism characteristics UHPC–NC clearly described. Finally, shortcomings application prospects interfacial properties highlighted.