Abstract
Mechanical properties of hybrid fibre-reinforced concrete (HFRC) are studied and the role of constituent fibres on overall response of HFRC is investigated. HFRC was produced using different proportions of hooked-ended steel, crimped polypropylene and plain Kevlar fibres with a total fibre volume fraction of 1.2% and 1.4%. The test results indicate that the incorporation of hybrid fibres in concrete improve the compressive and tensile strengths moderately and toughness considerably. Analytical models are developed to quantify the effect of individual fibres on compressive and tensile strengths, stress-strain curves and flexural toughness ratio of HFRC in terms of a comprehensive fibre reinforcing index. The proposed models show a marked improvement over existing models. The existing models are for single (steel) fibres only, whereas the proposed models are general and applicable to HFRC containing any number of fibres.