Study On Toughness Enhancement Effect Of High Strength Concrete By Joining Large Number Of Steel Fiber With Polypropylene Hybrid Fiber

High-strength concrete with its compared to ordinary concrete obvious technical advantages, in the application of practical engineering is more and more widely, but the concrete under certain loading will crack initiation and no signs of brittle failure problem is highlighted. Fiber into can prevent high strength concrete crack propagation and dissipation of high strength concrete fracture can, so as to improve the high strength fracture toughness of the concrete, is considered to be toughening brittle is the most effective method, and has been widely recognized and applied. Due to the concrete materials is a multi phase, multi structure, multi level non homogeneous composite structures, theoretically, if only the incorporation of single fiber will only improve a phase, a structure, a certain level of performance; so if you want to comprehensively improve the overall performance of the concrete and doped fiber should be multi-level mixed. The high and low elastic modulus fibers can be mixed in the concrete, which can show the advantages of different fibers, and obviously improve or improve the performance of single fiber reinforced concrete.A large number of studies show that, with the increase of steel fiber content, the toughness of concrete is significantly improved, but the volume content of steel fiber is mainly less than 2%. In this paper, the toughening effect of C60 high strength concrete with high content of steel and polypropylene fiber is studied, and the results are as follows:(1) The mix proportion of C60 reference concrete is determined by trial and test;(2) The technical problems of high content hybrid fibers were solved by ordinary mixing process and fiber hybrid technique;(3) The compressive strength test of high volume steel polypropylene hybrid fiber reinforced concrete was carried out, and the influence of the high content of steel polypropylene hybrid fiber on the compressive strength of concrete was obtained;(4) The high dosage of steel polypropylene hybrid fiber reinforced concrete flexural toughness test, through the load deflection curves of fiber concrete obtained respectively by flexural toughness index, equivalent bending strength and flexural toughness than research methods analysis the high dosage of steel polypropylene hybrid fiber on concrete flexural toughness were investigated;(5) To the high volume of steel and polypropylene fiber reinforced concrete splitting tensile toughness test, through the load deflection curves of fiber concrete obtained respectively by flexural toughness index, equivalent flexural strength and flexural toughness than research methods analysis the with high content of steel polypropylene hybrid fiber on concrete splitting tensile toughness of hybrid.(6) With high content of steel polypropylene hybrid fiber concrete dynamic splitting tensile toughness test, fiber concrete dynamic splitting tensile failure by the dissipation energy as a measure of the toughness of the evaluation criteria, analysis the different hybrid fiber proportion of C60 concrete dynamic splitting tensile toughness were investigated; and the whole failure process of specimen were recorded in by high-speed photography.