EXPERIMENTAL INVESTIGATION ON SHEAR STRENGTH OF SFRC BEAMS REINFORCED WITH LONGITUDINAL TENSION STEEL REBARS

In the present work, an attempt is made to investigate shear strength and ductility of fiber reinforced concrete beams by using hooked steel fibers. All the test beam specimens were 100 mm in width, 150 mm in depth and 1200 mm in length and the primary variables of the investigation were percentage of fibers (0.5 to 5 %), percentage longitudinal tension steel (0.8 to 3.22 %) and cube compressive strength of concrete (in the range of 34 to 41 MPa), with a view to cover a wide spectrum of concrete strength in shear. The shear span-to-depth ratio (a / d ratio) was kept constant at 3.20. This has resulted into casting and testing of twenty SFRC beam specimens. All the beam specimens were tested under four-point loading (2-active, 2-passive) test set-up and the failure load, crack pattern and deflections were recorded concisely and precisely. The experimental results clarify the enormous influence of hooked mild steel fibers on shear strength of concrete. At low fiber volume fraction, the influence of fibers is negligible and is significant with the increase in the fiber volume fraction. The concrete beam specimens exhibited substantial increase in their ultimate load as well as in the load at first cracks, enhanced deformation characteristics at all stages of loading up to failure. In general, the significant improvement in various strengths is observed with the inclusion of steel fibres in the plain concrete. However, maximum gain in strength of concrete is found to depend upon the amount of fibre content.