Mechanical and durability properties of sisal-Nylon 6 hybrid fibre reinforced high strength SCC

•Improvement of mechanical and durability properties of SCC by natural-synthetic hybrid fibers.•Hybridization take care of the synergetic action of both fibres.•Sisal fiber and Nylon 6 are used as natural and synthetic fibers.•Observed increased performance in strength and durability by hybridization. The higher paste volume in Self Compacting Concrete (SCC) makes it susceptible to have higher creep coefficient and cracking. Microcracks which are developed during the process of hardening of concrete makes the composite weak. This inherent internal flaw in concrete can be healed by blending it with fibre. A single fibre may be competent only for a narrow range of strain and crack growth rate, hence, may be ineffective for the comprehensive improvement of strength or ductility of concrete. This emanates in Hybrid Fibre Reinforced Concrete which acquires the advantages from the synergistic action of blended fibres. In this study, high strength SCC is developed with sisal-Nylon 6 mono and hybrid fibre combination proportioned at 0/100, 25/75, 50/50, 75/25 and 100/0 of total fibre volume. It is observed that hybridisation improved the flexural and tensile properties vis-à-vis mono fibre mixes. Also the stress-strain and ductility behaviour are augmented by hybridisation. The developed fibre reinforced concrete underwent acceptable water absorption and prevents chances of fibre deterioration which affect concrete durability. Even though nylon enhances mechanical properties it induces durability issues when exposure is considered. A statistical analysis using ANOVA is carried out to prove the effectiveness of hybridisation and fibre volume on mechanical properties of hybrid fiber reinforced self-compacting concrete.