Steel Fiber Moderate Aggregate Concrete Tensile Performance Test Research

The specified density steel fiber concrete is a new type of composite material which is mixed in the combined aggregate concrete with short steel fiber. The steel fiber has good tensile strength, scattered distribution in concrete. This can prevent the propagation of micro crack and macro crack in concrete and improve the tensile strength, flexural strength and shearing strength of specified density steel fiber concrete. Its shock resistance, fatigue resistance and fracture toughness also have bigger improvement. At present, the research on specified density steel fiber concrete is still relatively small at home and abroad.This paper uses orthogonal design method, through the experiments of cube splitting tensile strength and axial tensile strength, analyzes the water-cement ratio, lightweight replacement rate and steel fiber replacement rate and other factors on tensile strength of specified density steel fiber concrete. The toughening effect of steel fiber on concrete is also suggested. According to research objective,25groups of mix proportion and225test block have been made including cube compressive strength test, axial tensile strength test and splitting tensile strength test.The test result shows that:(1)The addition of steel fiber could improve the tensile performance of combined aggregate to some extent.(2)Steel fiber has good toughening effect which could make the test block of concrete destruction of crack without powder.(3)The ratio of splitting tensile strength and cube compressive strength is between1/9-1/15, the ratio of axial tensile strength and splitting tensile strength is about0.79.(4)With the increase of the volume fraction of steel fiber, elastic tensile modulus is rising somewhat. And apparent density is also affected little.The results of this paper can provide a reference for research and engineering application of specified density steel fiber concrete.