Experimental Analysis And Application Research Of UHPC

UHPC (Ultra-High performance concrete) is a new cementitious material with high strength, high toughness and high durability. By using the excellent material properties of UHPC in building structure, road and bridge, it can reduce the weight of structure, and increase the service life and durability of the structure.This paper mainly studies the influence of different steel fiber volume content on the working performance and mechanical properties of UHPC. Through the application of UHPC with ultra high performance to continuous girder bridge, the design of bridge structure form was optimized, in order to achieve a thinner and lighter bridge structure, but also to solve the problem that traditional concrete girder bridge usually faced, such as big self weight, the excessive deflection in the centre span, easy cracking. The research work of this paper is mainly carried out from the following three aspects:(1) By using Shanghai local raw materials, UHPC was prepared by adding different volume content of steel fiber to the matrix concrete. The effects of volume fraction of steel fiber on the flow properties and mechanical properties of UHPC were studied through UHPC expansion test, cube compressive test, splitting tensile test and beam bending test.(2) Taking Changchong Bridge as the engineering background, space finite element model was built by using the Midas software, in terms of the strength and stiffness of the bridge, the UHPC continuous girder bridge was optimized from height of the beam, plates thickness, prestressed reinforcement. Based on the parameters characteristics, the appropriate objective function and boundary conditions is select to optimize the bridge.(3) Contrast analysis of the optimized UHPC continuous girder bridge and original continuous girder bridge in terms of overall stress, torsion performance, static characteristics, economy and durability. The results show that the UHPC continuous girder bridge has superior mechanical properties, more material saving than ordinary concrete continuous girder bridge.