Behaviour of steel fibre reinforced self compacting concrete beams in flexure

The addition of steel fibre to Self Compacting Concrete (SCC) imparts superior mechanical properties to concrete. The workability and strength performance in fresh and hardened state of SCC containing steel fibres having aspect ratio 55 and volume fractions 0%, 0.5%, 1.0% and 1.5% of M30 grade were taken to study the effect of fibre content. Fly ash has been used as partial replacement of cement by a constant 18% for all mixes. In addition, eight nos. of steel reinforced beams having size 125 x 150 x 1100 mm have also been cast, cured normally and then tested under two point loading for flexural strength. The workability results of Steel Fibre Reinforced Self Compacting Concrete (SFRSCC) satisfy all properties of self compaction as per EFNARC specifications. It is observed that a marginally higher compressive strength, split-tensile strength and flexural strength has been found with 1% volume of steel fibres as compared to 0.5% and 1.5% of steel fibre content. Maximum values of ductility factor, energy absorption capacity and toughness index were found to be 2.86, 194.20 kN-mm and 5.05 respectively for SFRSCC beams with 1% steel fibres. Also, the toughness index, ductility factor and energy absorption of SFRSCC beam increased with increase in fibre content up to 1% beyond which it decreased marginally for 1.5% steel fibre content. (author)