Experimental study on the confinement of high-strength concrete columns with large rupture strain FRP composites

High-strength concrete (HSC) is finding increasing use in multi-storey construction in recent years. The performance of such structures can, however, be compromised by the high stiffness and low ductility of HSC. Confinement of HSC columns with fibre-reinforced polymers (FRP) can alleviate these shortcomings. To date, research attention on confinement is primarily focused on FRP composites with rupture strains up to approximately 3%, although recently introduced polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) fibres exhibit rupture strains of up to 10%. The use of HSC with large rupture strain (LRS) FRP composites in confinement applications is highly attractive because the efficient combination of these high-performance materials can lead to very high-performance columns. This paper presents an experimental study on the compressive behaviour of circular HSC columns confined with LRS FRP and traditional FRP composites. Results show that LRS FRP-confined columns exhibit similar strength enhancement to those traditional FRP-confined columns, however the ductility is significantly improved. In addition, the LRS FRP-confined HSC columns experience strength softening after concrete crushing.