The Performance And Calculation Method On The Compression And Splitting Tension Of Concrete Reinforced By The Steel Fibers With Hooked-end

With the future development of steel fibers in water conservancy projects,the steel fibers in concrete have developed from traditional low strength to high strength,single anchor type to high anchor type.Typical are the emergence of high-strength 3D steel fibers with single hooked end,as well as 4D and 5D steel fibers with multiple hooked-ends.Although a small amount of existing literature has conducted preliminary research on the mechanical properties of new steel fiber reinforced concrete(SFRC)with hooked-end,it is still in the exploratory stage and the related research results are relatively limited.Presently,it is necessary to conduct a more in-depth and systematic study of the basic mechanical properties and strengthening mechanisms of new SFRC with hooked-end.In this article,the effects of concrete strength grade(C25?C80),steel fiber content(0?110 kg/m~3),fiber aspect ratio(65?100),fiber length(35?60 mm)and fiber shape(3D,4D and 5D)on the working performance of fresh concrete and compressive strength,splitting tensile strength and tension-compression ratio of SFRC were investigated.Moreover,the relevant calculation method was proposed.The main research contents are presented as follows:(1)The results of working performance of 85 groups mixture proportions were conducted to investigate the effects of concrete strength grade,steel fiber content,fiber aspect ratio,fiber length and fiber shape on the working performance.The results indicate that the content of water reducer increases with the increase of concrete strength grade and steel fiber content for controlling the working performance of fresh concrete.But the working performance was mildly influenced by the steel fiber aspect ratio,length and shape.(2)Based on the compression test of 255 specimens of 150 mm×150 mm×150mm,the effect of concrete strength grade,steel fiber content,fiber aspect ratio,fiber length and fiber shape on compressive strength were studied.It is indicate that the compressive strength increases with higher concrete strength grade.The strength goes upward first and then drop down with increasing the steel fiber content within 20?110kg/m~3and the rate of increase is limited with a maximum of 15%.But the compressive strength was mildly influenced by the steel fiber aspect ratio,length and shape.(3)Based on the splitting tensile test of 255 specimens of 150 mm×150mm×150 mm,the effect of concrete strength grade,steel fiber content,fiber aspect ratio,fiber length and fiber shape on splitting tensile strength were studied.The results indicate that the splitting tensile strength increases with the increase of concrete strength grade.Increasing the steel fiber content is the most useful way to increasing splitting tensile strength.The maximum rates of increase of C40?C60 and C80 specimens are 114.7%?103.81%and 161.29%,with increasing the steel fiber content within 20?110 kg/m~3.The splitting tensile strength also increases with the increase of steel fiber aspect ratio,length and shape,but the effects are much smaller than steel fiber content.(4)The results of the tension-compression ratio of 85 groups mixture proportions were conducted to investigate the effects of concrete strength grade,steel fiber content,fiber aspect ratio,fiber length and fiber shape on the tension-compression ratio.The results indicate that the tension-compression ratio increases with the increase of concrete strength grade and steel fiber content.The maximum rates of increase of C40?C60 and C80 specimens are 114.7%?103.81%and 161.29%,with increasing the steel fiber content within 20?110 kg/m~3.The tension-compression ratio also increases with the increase of steel fiber aspect ratio,length and shape,but the effects are much smaller than steel fiber content.(5)Based on the effects of concrete strength grade,steel fiber content,fiber aspect ratio,fiber length and fiber shape on the working performance of fresh concrete and compressive strength,splitting tensile strength and tension-compression ratio of SFRC with hooked-end and analysis of steel fiber reinforced mechanism,the relevant calculation method was proposed.