Study On Key Mechanical Properties Of Steel Fiber Polymer Structural Concrete

In order to make better use of the excellent mechanical properties of steel fiber polymer concrete which is a new type of building materials, and promote its using in the large span bridge structure, this study conducts the secondary development of “steel fiber reinforeed Polymer modified concrete” with independent intellectual property rights to develop a new composite material named steel fiber polymer struetural concrete(SFPSC) which will be better able to meet the demand of large span bridge structure. This article explores the key mechanical properties of statics performance, environmental fatigue performance, structural mechanics performance, anti-deforming capability, anti-cracking performance with using experimental method, numerical analysis combines the oretical derivation method. The main research contents and conclusions are as follows:1)Introduced the design target, basis of designing, mix composition of this new composite material. The statics performance of SFPSC was tested, it showed that the flexural strength and splitting tensile strength could be significant improved with the right amount of polymer and steel fiber.2) In view of the bad climatic environment in guangdong area of Bridges servicing, this research carryed out the targeted hot-wet-load coupling environment of three point bending fatigue experiment in three different humidity conditions(23℃、78%R.H;50℃、80%R.H;50℃、95%R.H;), obtained the fatigue equation and S ~ N curve, and found: the more bad experimental atmospheric environment was, the smaller its fatigue limit(Sf) would get; the more bad experimental atmospheric environment was, the more gentle S~N curve slope would get, also means the specimen beams was more sensitive to cyclic loading.3) According to the test data of this environment fatigue, combined with the classical theory of fatigue strength theory, the fatigue life formula was successfully deduced under the hot-wet-load coupling environment. The SFPSC fatigue limit and fatigue life could be effectively and conveniently predicted using this formula under hot-wet-load coupling environment of three point bending fatigue experiment.4) The structural mechanics performance had been comparatively calculated with SFPSC materials and C55 concrete which have a compressive strength by building a finite element using MIDAS CIVIL software. By comparing the flexural bearing capacity, shear bearing capacity, anti-deformation capacity of box girder structure which were composed by the two kinds of material, found the flexural bearing capacity, shear bearing capacity, anti-deformation capacity of the box girder structure did not reduce, but each had different degrees of increase.5) Intercepting the internal section forces of MIDAS CIVIL model to build the ANSYS WORKBENCH entity model, and calculated the tensile stress of 0# part, compared the anti-cracking performance between the SFPSC material and C55 concrete which had the compressive strength, found out that the C55 concrete could not meet the requirement of the bridge anti-cracking performance, and the SFPSC material had a better crack resistance, which could basically met the requirements of large prestressed concrete rigid-frame bridge.