Bond behavior of reinforcing steel in ultra-high performance concrete.

2014PDFTech ReportFHWA-HRT-14-090Ultra high performance concreteFiber reinforced concreteReinforcing steelBond strength (Materials)Reinforcing barsDeformed barsTensile strengthCompressive strengthUnited StatesUnited States. Federal Highway Administration. Office of Infrastructure Research and DevelopmentYuan, JiqiuGraybeal, Benjamin A.United States. Federal Highway Administration. Office of Infrastructure Research and DevelopmentFederal Highway AdministrationUltra-High Performance Concrete (UHPC) is a relatively new class of advanced cementitious compositematerials, which exhibits high compressive [above 21.7 ksi (150 MPa)] and tensile [above 0.72 ksi (5 MPa)]strengths. The discrete steel fiber reinforcement included in UHPC allows the concrete to maintain tensilecapacity beyond cracking of the cementitious matrix. The combination of the matrix and fiber performance allowfor a reduction on the development length of reinforcing bar, thus providing the potential for a redesign of somestructural systems such as field\u2013cast connections between prefabricated bridge elements. The bond behavior ofdeformed reinforcing bar in UHPC is investigated in this study by conducting direct tension pullout tests. Over200 tests were completed and the effect of embedment length, concrete cover, bar spacing, concrete strength, barsize and type on bond strength were investigated. It was found that the development length of embeddedreinforcement in UHPC can be significantly reduced. Guidance on the embedment of deformed reinforcing barsinto UHPC is provided.This report corresponds to the TechBrief titled \u201cBond Behavior of Reinforcing Steel in Ultra-High PerformanceConcrete\u201d (FHWA-HRT-089)