Axial compressive behavior of recycled ceramic coarse aggregate concrete-filled steel tubular columns

A series of axial compressive tests were performed on recycled ceramic coarse aggregate concrete (RCCAC) cubes and prisms, as well as 36 recycled ceramic coarse aggregate concrete-filled steel tubular stub columns (RCCAC-FSTs) in the present study. RCCAC failure mechanisms, compressive strength, elastic modulus, and micro-structure were studied. In addition to the cross-sectional type, the steel content, the confinement factor, and the replacement ratio of recycled ceramic coarse aggregate (RCCA) were chosen as primary variables to investigate the passive confinement effect of RCCAC-FSTs. Analysis of the typical failure modes, the Load (Nue)-longitudinal strain (& epsilon;L) curve, the Load (N/Nue)-hoop strain (& epsilon;h) curve, the ultimate bearing capacity, the ductility, and the effect of RCCA replacement ratio were successively performed. The results suggest that the confinement factor determines the development pattern of the load-strain curves, while the use of RCCA influences the failure mode, the elastic modulus, the ultimate strength, the critical strain, and the ductility of specimens. The critical confinement factor for circular and square specimens was also determined. A stress-strain model of RCCAC restrained by steel tube was established and verified through finite element analysis based on a database of test results presented in the present study and existing research.