Steel fiber reinforced shotcrete or concrete (SFRC) is used for supporting of slope and tunnel when condition is severe. Steel fibers in shotcrete is considered to improve crack
In this study, uniaxial tensile tests of SFRC was conducted by servo-controlled testing machine to obtain complete stress-strain curves. In the experiment, volume fraction of steel fiber in shotcrete was chosen to be 0, 0.5, 1.0, 1.5 %. Considering anisotropy of SFRC, two kinds of cylindrical specimens were made boring parallel and normal to bedding plane.
The experimental results in uniaxial tension can be summarized;
1) The strength and residual strength indicate anisotropy of SFRC. Both are larger when stress is applied parallel to bedding plane.
2) The strength and Young's modulus were not affected with volume fraction of steel fiber (Vf [%]), however the residual strength (σRE [MPa]) increases following the equation, σRE=5×10-6×(12.5-Y) 5×Vf where Y [mm] is displacement.
3) In residual strength region beyond peak strength, steel fibers are gradually pulled out from shotcrete. The residual strength is caused by pulled out resistance of steel fibers.
4) The number of steel fiber appeared on the fractured surface is smaller than that on cutting surface. Fractured surface tends to develop on the weakest plane where relatively a small number of fibers cross the plane.
