Evaluation of shear strength in self-com parting fibre-reinforced concrete and conventional concrete deeo beams

摘要

Self-compacting concrete (SCC) offers several benefits over conventional concrete (CC), mainly the ease in placement and lack of vibration. The uses of SCC with fibres extend its possibilities. As fibres are known to significantly affect the workability of concrete, primarily investigation was carried out to finalise the possible content of steel and polyester fibres by various fresh property tests of SCC as per EFNARC specifications. The use of concrete deep beams is gaining rapid popularity in modern construction industry owing to the requirement of column-free space. There is some concern among researchers and designers that SCC may not be strong enough in shear because of the smaller amount, smaller size and the weak interlock mechanism of coarse aggregate. In the case of deep beams, shear failure is prominent and the aim of further research is to investigate the shear strength and deformation characteristics of SCC with and without fibres for various span-to-depth ratios of deep beams in comparison with conventional concrete. Based on the fresh property test results of SCC with fibres, steel fibres produced more hindrance in flow than polyester fibres, whereas in the hardened state steel fibres showed better strength. In deep beams, the shear capacity of SCC was 35-45% lower than that of CC. The shear capacity of the SCC deep beams was increased 25-35% by the inclusion of steel fibres. However, insignificant and unrewarding results were produced by polyester fibres.