Study on mechanical properties of concrete reinforced with hybrid fibers at a low fiber volume fractions

Abstract

This study is aimed to investigate the effect of fiber hybridization on basic mechanical properties of 30 MPa concrete. Fibers used in the study are Hooked-end steel, polyester and polypropylene. Hybridization was done in two stages, the first stage of the investigation was to develop and study the effect of polyester-polypropylene (Non–metallic) HFRC at a total fiber volume fraction of 0.15%. Further, the investigation was carried out to develop a hybrid fiber reinforced concrete made with metallic (hooked-end Steel) and non-metallic fibers at a total fiber volume fraction of 0.5%. Mechanical properties, namely compressive strength, direct tensile strength and flexural strength were investigated. The results obtained were compared with mono-fiber reinforced concrete and conventional concrete. Significant improvement in direct tensile strength and flexural strength observed with the with the fiber hybridization compared to mono-fiber reinforced concrete and control mix. This may be due to synergic response of different fibers at different scales of cracking at different stress levels in concrete. Superior results were observed at metallic – non-metallic hybridization due to exhibition of synergetic response of fibers by inhibition of crack growth and propagation, at different scales of cracking at different stress levels in concrete.