Mechanical properties of high-strength concrete with hybrid fibre reinforcement

The brittle failure of plain concrete can be avoided by incorporating randomly distributed short fibres which make the concrete more tensile and absorb more energy. This paper investigated the influence of steel-polyolefin hybrid fibres and steel fibres in comparison with plain high strength concrete having compressive strength of 60 MPa by measuring the physical properties such as compressive strength, splitting tensile strength, flexure strength and toughness index. The steel fibres were added at the volume fraction of 0.5%, 1.0%, 1.5% and 2.0%. Steel-polyolefin fibres were hybridized at 80%–20% and 60%-40% combination at each volume fraction. Test results showed that the fibres when used in hybrid form could result in enhanced flexural toughness compared to steel fibre reinforced concrete [HSFRC]. The compressive strength of the fibre-reinforced concrete reached maximum at 1.5% volume fraction and the splitting tensile strength and modulus of rupture improved with increasing volume fraction. Also the investigation shows that there is an enhancement of flexural rigidity and reduced number of cracks and length and width of cracks in concrete with hybrid micro-reinforcement than of concrete with steel fibres only.