Effect of hybrid steel fibres on shear behaviour of self compacting RC beam

Self-compacting concrete (SCC) has proved to be beneficial in the construction sector as it lowers the time to build as well as the cost of construction. The addition of steel fibres into the SCC mix delays the propagation of microcracks and macrocracks depending upon the geometrical parameters of the fibres. Further, reinforced steel fibres turn the brittle SCC concrete mix into acquiring ductility. Many studies are available on the structural behaviour of the fibre-reinforced self-compact concrete (FRSCC), but the studies on Hybrid Steel Fibre-Reinforced Self-Compacting Concrete (HSFRSCC) is scarce. In this research, the impact of the addition of hybrid steel fibres (a combination of micro steel and hooked-end steel fibres of varying proportions) on the shear behaviour of SCC was investigated. Two different volume fractions of fibres – 0.4% of hooked end with 0.1% of micro steel fibres and 0.5% of hooked end with 0.25% of micro steel fibres was considered for investigation. The addition of hybrid steel fibres greatly enhanced the shear characteristics of the SCC beam. In particular, adding shear reinforcement with hybrid steel fibres to the SCC beam enhances shear capacity by 44.98% and reduces the crack width and spacing by 50% and 48% respectively.