SUMMARY
The present study investigated on the mechanical characteristics of different types of steel fibre substituted high strength concrete. Influence of steel fibre volume fraction and its complex profile characteristics on the strength properties of various fibre substituted concretes had been systematically studied in slender concrete beam sections. Reinforcing efficiency of concrete incorporating four types of steel fibres having same aspect ratio with varying fibre profile - single hooked ends, crimped, double hooked ends and kinked had been experimentally analyzed in flexural bending and fracture studies. Test results showed higher flexural post crack toughness (23.48 N-m) and fracture toughness (39.62MPavmm) for double hooked steel and crimped steel fibres substituted concretes. Steel fibre concretes containing double hooked and kinked geometry exhibited higher ductility ratio and overall performance index. Also, high volume steel fibre substitutions (1.5% Vf) in slender concrete beams showed improved post crack ductility and characteristic length.