Study On The Influence Of Steel Fiber Types On The Mechanical Properties And Durability Of Basalt Fiber Concrete

The incorporation of steel fiber and basalt fiber can improve the mechanical properties and durability of the concrete part,but the steel fiber has a large weight,is easy to rust,and has poor fire resistance.The basalt fiber has light weight,corrosion resistance and high temperature resistance.Therefore,the two types of fibers are mixed in the concrete in a certain proportion,which can complement each other.Finally,a solution with better overall performance is obtained.In this paper,we tried to double-mix wavy steel fibers,copper-plated steel fibers and end-hooked steel fibers with basalt(0.1%)fibers at 0.8%,1.0%,and 1.2% in concrete.Firstly,mechanical properties tests were conducted to analyze the change of concrete strength with different steel fiber types and admixtures.After that,freeze-thaw cycle tests were conducted to study the effect of different steel fiber admixtures and types on the concrete under the same medium(3.5% Na Cl)and its variation law.Finally,the pore distribution of concrete was analyzed by NMR technique to study and analyze the freeze-thaw damage mechanism of fiber concrete.Through the test:(1)steel fiber doping in the range of 0.8%-1.2%,the highest end-hook steel fiber compressive strength at 1.0% doping,an increase of 25.3%.The splitting tensile strength was the highest,with an increase of 66%.Flexural strength is also the highest,an increase of 67.3%.(2)The end-hook type steel fiber with 1.0% steel fiber doping has the highest resistance to mass loss.Freeze-thaw cycles for 175 times its relative dynamic modulus of elasticity of 57.89%,is the latest to reach the test stopping conditions.Therefore,the end-hook type steel fiber with 1.0% steel fiber doping has the best durability.(3)It was concluded from the NMR test that the XW/0.1 group of concrete specimens had the most pores and the largest proportion of harmful pores,and the DG/1.0 group had the smallest proportion of harmful pores,although the pores were not the least.(4)In summary,the end-hook type steel fiber with a volume dose of 1% in the range of 0.8%-1.2% is the optimal solution for mechanical properties and durability.