Interface Shear Failure Behavior Between Normal Concrete (NC) and Ultra-High Performance Concrete (UHPC)

• Published in: International journal of concrete structures and materials Vol. 18; no. 7; pp. 1411 - 1426
• Main Authors: Zhang, Boshan, Yu, Jiangjiang, Chen, Weizhen, Chen, Jianbo, Li, Heng, Niu, Jialun
• Format: Journal Article
• Language: English
• Published: Singapore 한국콘크리트학회 01.12.2024; Springer Nature Singapore; Springer Nature B.V; SpringerOpen
• Subjects: Building Materials; Concrete; Engineering; Failure modes; Interface roughness; Interfacial shear failure; Interfacial shear strength; Mechanical properties; Microstructure of ITZ (interface transition zone); NC–UHPC interface; Shear forces; Shear strength; Shear tests; Solid Mechanics; Structural Materials; Substrates; Ultra high performance concrete; Ultra-High-Performance Fiber-Reinforced Concrete (UHPFRC) with low embedded carbon; 토목공학; Interfacial shear failure; NC?UHPC interface; Microstructure of ITZ (interface transition zone); Interface roughness; NC–UHPC interface
• DOI: 10.1186/s40069-023-00657-6
• ISSN: 1976-0485; 2234-1315

Ultra-high performance concrete (UHPC) with excellent mechanical properties and durability is a promising material for reinforcement of existing normal concrete (NC) structures. In this paper, the shear failure behavior of the NC–UHPC interface was studied by the slant shear test and the SEM (scanning electron microscope) visualization test, considering influence of the substrate strength and the interface roughed treatment. As the NC substrate and the UHPC overlay are tightly combined at the interface transition zone (ITZ), the interface exhibits good slant shear performance, and the measured interfacial shear strength could reach 19.4 MPa with C40 substrate and 21.8 MPa with C50 substrate. In addition, the microstructure and composition of the ITZ, the possible interfacial failure modes, and the load-carrying mechanism of the interface under compression–shear force are revealed. The high interface roughness and the substrate strength have positive influence on the shear strength, and greatly affect the prone failure mode and the load-slip characteristic.