关键词: 桥梁伸缩缝;超高性能混凝土;混杂纤维;常温养护;工程应用

Abstract: Based on the theory of hybrid fibers, an improved ultra high performance concrete ( UHPC) is proposed after the optimization of different hybrid fibers, including PVA fiber or polypropylene ( PP) fiber and steel fiber, which realizes the curing under the normal temperature.The application of the proposed UHPC used in the repair of the transition of the bridge expansion joint is discussed.The research results show that the hybrid fiber reinforced UHPC has high strength and good crack resistance when the addition of the PP fiber is 20 kg/m3.The flexural strength and compressive strength of UHPC samples can amount to 13.6 MPa and 40.9 MPa when the curing time is 2 d, respectively, and 51.3 MPa and 138.5 MPa when the curing time is 28 d, respectively.The phenomenon of the shrinkage crack isn't clear during the shrinkage slab test.Engineering practice indicates that the proposed UHPC used in the repair of bridge expansion joint can not only satisfy the service performance, but also quickly restore the traffic, which has broad application prospects

Key words: bridge expansion joint;ultra high performance concrete;hybrid fiber;curing under normal temperature;engineering application