Experimental Study On Shear And Splitting Tension Properties Of Aligned Steel Fiber Reinforced Cement-based Composites

Concrete is a brittle material with poor deformation capacity.When shear failure happens,concrete is very abrupt and belongs to the typical "one crack or bad".The shear failure of beam column joints,shear walls and initial masonry structures requires better shear strength of concrete.Steel fiber has a good effect of reinforcing and toughening on concrete,which obviously improves the defect of concrete.After the shear crack is produced in the concrete,the bridging effect of steel fiber in the cracks makes the concrete continue to bear the shear load and control the speed of the crack,thus the shear strength and the shear toughness of the concrete have been improved.Due to the random distribution of steel fiber in concrete,the reinforced shear strength of steel fibers in different directions is in big difference.In this article,the shear properties of the aligned steel fiber reinforced cement-based composites are studied around the influence of the distribution direction of steel fiber on the shear properties.In the process of shear failure,the steel fiber will be pulled out of the matrix.Therefore,the tensile properties of the aligned steel fiber reinforced cement-based composites are indirectly studied by the splitting tensile test.The main work and achievements of this article are as follows:(1)The shear strength,the shear load-displacement curves and the shear stress-strain relationships of the aligned and ordinary steel fiber reinforced cement-based composites are obtained by modified double-plane shear test and the image analysis method.The experimental results show that the shear strength,shear toughness and shear modulus of aligned steel fiber reinforced cement-based composites have been improved compared with ordinary steel fiber reinforced cement-based composites,showing a higher shear ability.(2)Through the establishment of the theoretical analysis and the shear model,it is known that the reason for the enhancement of the shear properties of the aligned steel fiber reinforced cement-based composites is related to the distance between the steel fibers and the energy consumption of the shear deformation.Compared with the ordinary steel fiber reinforced cement matrix composites,the aligned steel fiber reinforced cement-based composites have smaller fiber spacing,higher energy consumption when the sheardeformation occures,and greater friction between the shear plane.Therefore,the shear properties of the aligned reinforced cement-based composites are better.(3)The splitting tensile test of steel fiber reinforced cement-based composites shows that the aligned steel fiber reinforced cement-based composites have higher splitting tensile strength.This shows that when shear failure occurs,the aligned steel fibers need greater load when they are pulled out of the matrix,so the shear ability of aligned steel fiber reinforced cement-based composites is stronger.