Flexural performance of fibre reinforced concrete made with steel and synthetic fibres

The ductility of concrete made with commercially available steel and synthetic fibres has been investigated. Flexural stress–deflection relationships have been used to determine: flexural strength, flexural toughness, equivalent flexural strength, and equivalent flexural strength ratio. The flexural toughness of concrete was found to increase considerably when steel and synthetic fibres were used. However, equal dosages of different fibres did not result in specimens with the same flexural toughness. Flexural toughness differences of almost 35 J existed even at the same fibre dosage. This also resulted in considerable differences in the minimum required ground supported slab thickness.

► Fibres do not significantly improve the flexural strength. ► The main benefit of fibres is the improved ductility in the post-crack region. ► Flexural toughness increases considerably when steel and synthetic fibres are used. ► The required slab thickness was found to reduce as the fibre dosage was increased. ► The thickness of the slabs was also influenced by the type and shape of the steel fibres.