Axial compression performance of CFST columns reinforced by ultra-high-performance nano-concrete under long-term loading

Abstract The addition of nano-silica to ultra-high-performance concrete (UHPC) increase its toughness has been proposed obtain nano-concrete (UHPNC). This work mainly studies the reinforcement effect UHPNC on filled steel tube (CFST) columns under long-term load. Ten CFST strengthened with were selected and reinforced UHPNC. influences different thicknesses layer contents axial compression properties specimens studied, by loading in two steps: load ultimate study discussed failure modes, compressive toughness, bearing capacity, initial stiffness, ductility coefficient specimens. results show that outsourced method is an effective improve performance during service period. With thickness layer, capacity column increases greatly. increased content thickness. decrease rate stiffness content.