The Research On The Dynamic Performance Of Grading Steel-fiber Reinforced Reactive Powder Concrete

The objective of this thesis is to investigate the mechanical performance of grading steel-fiber reinforced Reactive Powder Concrete(RPC) by using a split Hopkinson Pressure Bar(SHPB). In this thesis, dynamic tensile behavior of grading steel-fiber reinforced RPC was studied by using the conic variable cross-sectional SHPB with a 74mm diameter. Comparatively, dynamic compressive behavior of grading steel-fiber reinforced RPC was studied by using SHPB with a 37mm diameter.The dynamic splitting tensile strength, compressive strength, tensile stress-time curves and compressive stress-strain curves under different strain rates were obtained, and were compared with the results of static tests. From the test results, dynamic tensile behavior and dynamic compressive behavior of steel-fiber reinforced RPC containing different kinds of steel fiber was discussed. The behavior of steel-fiber reinforced RPC containing all three kinds of steel fiber which had been grading was also discussed. At last, we summarized strain rate effect of grading steel-fiber reinforced RPC, and the factors that affect dynamic tensile behavior and dynamic compressive behavior of steel-fiber reinforced concrete.At first, the research development of steel-fiber reinforced RPC inside and outside country and the basic principle of the test sets were introduced in this thesis. Then, basing on the research content, the raw materials, mixture ratio and methods of tests were ascertained. High strain rate dynamic splitting tensile tests of the70mm-diameter specimens were carried out by using the conic variable cross-sectional SHPB From the tests, it is discovered that strain rate effect of reinforcing exist in steel-fiber reinforced RPC ,and the kind of steel fiber significantly affect static and dynamic tensile strength and ductility .The reinforcement effect of steel fiber was different under dynamic and static load .If the steel fiber is grading properly , not only will the tensile strength of RPC be high, but also the ductility of RPC will be improved.With different kinds of steel fiber and all three kinds of steel fiber mixing into concrete matrix, the influence of the kind and the grading of steel fiber on the RPC compressive behavior were investigated. From the tests, It is found that the reinforcement of different kinds of steel fiber is different, and different grading of steel fiber have little impact on the static and dynamic compressive strength,but have much impact on the ductility of steel-fiber reinforced RPC.