Mechanical performance analysis on RACFST under axial compression

In order to study the mechanical performance evolution of RACFST members under axial compression, sixteen specimens are tested according to the parameters of recycled coarse aggregate (RCA) replacement ratio and height-width ratio. Based on the tests, the axial compression load-displacement curves are obtained and the influences of test parameters on the energy dissipation, deformation ductility and stiffness of specimens are analyzed. Results obtained show that the biggest difference of load-displacement curves between circular and square specimens is that the peak point is very sharp in the curves of square specimens. With the increasing of RCA replacement ratio, the energy-dissipating capacity of short column specimens is reduced, while the energy-dissipating capacity of medium length circle steel tube specimens is enhanced, and the trend of energy-dissipating capacity for medium length square steel tube specimens is firstly reduced and then raised, moreover, the deformation ductility of all specimens keeps increasing. With the increasing of height-width ratio, the axial compression energy dissipation of RACFCST keeps a trend of reduction-increase-decrease, while the axial compression energy dissipation of RACFSST is reduced. In addition, the ductility coefficient of medium length specimens keeps declining as a whole. With the increasing of RCA replacement ratio, the relative elastic stiffness of RACFT keeps increasing.