Study On Fracture Mechanical Properties Of Reactive Power Concrete

RPC is a new kind of composite material,the research on its fracture properties is just in the starting stage.Few literatures have quantitatively analyzed the fracture parameters,and there are fewer literatures which further research on its fracture behavior and give some qualitative analysis.The tests prepare high-strength concrete(C80)and RPC with 0%,0.5%,1.0%, 1.5%,2.0%steel fiber volume ratio 3-point bending beam.The size of the beams is 400×100×100 mm,the ratio of slit and depth is 0.40.The curves of load-displacement and load-crack mouth opening displacement are measured in the tests.Calculation theory is fictitious crack modle and linear elastic fracture mechanics.The basic mechanical properties and fracture behaviors of these two materials are preliminarily studied.The thesis studies the influencing factors of basic mechanical properties and fracture behaviors,such as cubic compressive strength,splitting tensile strength, fracture energy,fracture toughness and effective length of critical crack.The factors include material type and steel fiber volume ratio.The results show that the fracture behavior of high-strength concrete(C80)is better than RPC without steel fiber,its fracture energy is 1.26 times of RPC without steel fiber;But the fracture behavior of high-strength concrete is worse than RPC with steel fiber,its fracture energy is 1/61～1/27 times of RPC with steel fiber,its characteristic constant is 1/6～1/5 times of RPC with steel fiber,its ductility index is 1/30～1/25 times of RPC with steel fiber,its fracture toughness is 1/10～1/5 times of RPC with steel fiber.The reinforcing and toughening effect of steel fiber is striking;The results demonstate that the fracture energy of RPC increases when improving steel fiber volume ratio,and the other parameters,such as fracture toughness,ductility index,characteristic constant and critical effective length of crack,donot show the same law.They donot change monotonously with the improving of steel fiber volume ratio,and the volume ratio of steel fiber has an optimal value,which is 0.5～1.0%.The thesis gives the relation of fracture parameters and the volume ratio of steel fiber according to the data of the test; The thesis also discusses the process and mechanism of fracture,analyzes the mechanism of reinforcing and toughening effect of steel fiber.