Tie-confined fibre-reinforced high-strength concrete short columns

Abstract

An experimental study was carried out to investigate the behaviour of steel fibre-reinforced high-strength concrete (HSC) short columns confined by square ties under monotonically increasing concentric compression. A total of 72 confined and 24 unconfined specimens were tested in this test programme. The test variables included aspect ratio and volume fraction of crimped steel fibres, volumetric ratio, yield strength and configuration of transverse tie reinforcement and concrete strength. The effects of these variables on the uniaxial behaviour of HSC short columns are presented and discussed. The results indicate that the addition of fibres to the HSC mix prevented the early spalling of the cover and increased the load-carrying capacity and ductility of the specimens over that of comparable non-fibre columns. The effect of mixed aspect ratio of fibres on the stress–strain behaviour of confined HSC was also studied by blending the short and long fibres. It is shown that a higher gain in column strength can be affected by the addition of shorter fibres, and longer fibres can provide better enhancements in the post-peak deformability.