INFLUENCE OF HYBRID FIBRES ON THE FLEXURAL PERFORMANCE OF SELF-COMPACTING CONCRETE

This paper discusses the experimental results of tests carried out on the flexural properties of hybrid fibre-reinforced concretes at low volume fractions of fibres upto 1%. Hybrid fibrous concrete was prepared by using both steel and polypropylene fibres. Steel fibres were replaced with various dosages of polypropylene fibres, compared to a reference concrete with 1% steel fibres. The flexural properties such as flexural strength, toughness, and ultimate strength, were measured using four-point bending tests on beam specimens. The best flexural performance was obtained at the hybrid combination of 0.9% steel and 0.1% polypropylene dosage. At this volume fraction, flexural toughness of hybrid fibre concretes were comparable to the mix containing only steel fibre. Optimum fibre availability in the hybrid fibre mixes and the ability of non-metallic fibres of bridging smaller micro cracks, are suggested as the reasons for the enhancement in flexural properties