Experimental Study on the Uni-axial Behaviour of MSCFST Columns Considering Concrete’s Wet Packing Density

Manufactured sand (MS), which is produced by mechanical crushing of rock depositions or construction wastes, has been adopted as one of the possible river sand (RS) succedaneum to make ‘Greener concrete’. In this study, the possibility of the application of MS concrete in concrete-filled-steel-tube (CFST) column has been investigated. A total of 5 CFST columns with MS partially or totally replacing RS have been prepared and tested under uni-axial compression. The main parameter was the MS replacement ratio (0%, 25%, 50%, 75% and 100%). From the experimental study, it is clear that by replacing RS with MS, the fresh and hardened properties of concrete varied. Besides, all the CFST columns failed by local buckling and as the MS replacement ratio increased, the local buckling seems more irregular. Moreover, the CFST columns showed different load-strain behaviour as the MS replacement ratio changed. The concrete’s wet packing density (WPD) is a better indicator than MS replacement ratio on the strength of concrete and the load-carrying capacity of CFST columns. In general, maximizing the WPD would enhance the strength of plain concrete and significantly improve the load-carrying capacity of CFST columns.