Distribution and orientation of steel fibres in steel fibre reinforced concrete

The use of fibres to reinforce brittle materials for better performance has been employed since time immemorial. Therefore, inclusion of steel fibres in concrete has always improved the post-cracking strength and concrete ductility to a large extent while full potential of steel fibre reinforced concrete (SFRC) is still yet to be exploited in practice. This study investigated the effects of fibre type, dosage and maximum aggregate size on distribution and orientation and hence, the flexural performance of steel fibre reinforced concrete. Hooked-end steel fibres with 50 mm and 60 mm length, aspect ratio of 45, 65 and 80, and dosages of 0 kg/m³, 25 kg/m³, 40 kg/m³, 50 kg/m³ and 60 kg/m³ were used with maximum sizes of coarse aggregate of 10mm and 20mm. X-ray Computed Tomography was employed for imaging cores taken from the slab specimens after testing. The experimental results show a remarkable improvements in flexural strength up to 83% observed at larger dosage of steel fibre and when good interaction leading to better distribution and orientation of fibres within concrete matrix is sustained between right fibre geometry and appropriately sized aggregate.