Workability Of Steel Fiber Reinforced Self-Compacting Concrete And Effectiveness Of Stirrups Partially Replaced By Steel Fiber

With the continuous expansion of infrastructure,structures have a growing trend in height,extent,span and novelty at home.Accordingly,more and more quality problems appeared with dense reinforcing bars,for example:when the concrete flows through dense bars,narrow or closed space(such as,T beams of long-span bridges,box girders, beam-column joints,beams,slabs and shell structure),segregation or even no-pass of the concrete would occur,which would influence normal use of construction.In order to solve those problems,western countries investigated and widely used fiber reinforced self-compacting concrete(FRSCC) which has a combined advantages from self-compacting concrete and fiber reinforced concrete.Presently,the studies and applications of SCC are mainly focused on its material properties,workability and strength.And the studies of FRC are mainly within its flexural toughness.Having carefully studied the previous researches both at home and abroad,this research, firstly,carries out an experimental investigation on the mix ratio and workability of C40 SCC. Numerous tests have been conducted to assure a better performance on fluidity,filling property and anti-segregating of the fresh self-compacting concrete.Then this research has done an experimental and analytical investigation on shear behavior of 9 rebar steel fiber reinforced self-compacting concrete beams under 4 points symmetry concentrated loads.Besides,the study emphatically discussed the basic effects of steel fiber content and stirrup ratio on shear behavior of beams,and effectiveness of stirrups partially replaced by steel fiber.Based on the experimental results,this paper analyzed the influence of steel fiber on initial shear cracking strength,width of crack,shear failure pattern,stirrup strain, load-deflection curve,ultimate strength and shear toughness.Based on the analysis of existing experimental results and on numerous shear test results of reinforced concrete beams in literature,this paper proposed formulas for the ultimate strength of rebar steel fiber reinforced self-compacting concrete beams,whose results are coincides well the experimental one.It also suggested the fiber enhancement factor of hooked steel fiber should be 1.78.Not only the ultimate strength would be enhanced,but also the performance after peak-load almost is same while stirrups partially replaced by steel fiber.