Flexural behaviour of hybrid fibre reinforced concrete beams made with various packing factors and fine to total aggregate ratio

Abstract

The objective of this study is to investigate the flexural behavior of M30 grade PSCC, GFRSCC, SFRSCC and HFRSCC beams made with PF=1.12 and s/a=0.53 and PF=1.14 and s/a=0.57 to understand the effect of copper slag as partial replacement of fine aggregate on its deflection characteristics and cracking behaviour. The yield and ultimate load taken by HFRSCC beams made with optimum PF and s/a ratios are higher than the conventional RCC beam elements. The deflections at centre at failure in HFRSCC beams made with optimum PF and s/a ratios were more than that of conventional beams. This shows improvement in ductility of HFRSCC beams. First crack formation was delayed in M30 grade HFRSCC beams due to dense micro structure with low pore fraction and reduced pore size due to which fatigue strength is increased which in turn increases the time taken for first crack occurrence and thereby increasing the load carrying capacity. The deflection at the mid span decreased in HFRSCC beams which shows that the flexural stiffness of the elements increases thereby reducing the structural member’s deformability, increasing strength and hence controlling deflection.