Properties of self-compacting recycled aggregate concrete and its impact on structural behavior of composite tube columns

This thesis mainly consists of two parts. First part covers the material characterization of recycled aggregate self-compacting concrete in terms of fresh, mechanical and fracture responses; while the second part of the thesis presents the research results on the structural behavior of the axially loaded steel tube columns filled with such concretes. Study parameters included single and combined uses of recycled fine and coarse aggregates, substitution levels, compressive strength of concrete core, cross-section slenderness (D/t ratio) and yield strength of steel tube. To this aim, the hardened concrete properties were evaluated in terms of compressive strength, splitting tensile strength, static modulus of elasticity and net flexural strength. Failure mechanism of the notched concrete beams was also monitored via three-point bending test to observe the ductility level with respect to the fracture parameters. The statistical analysis based on GLM-ANOVA was also performed to assess the significance of the test parameters. Furthermore, comparison and code assessment for the axial load carrying capacity of the recycled aggregate concrete filled steel tube composite columns were studied by using four different design code equations (American Concrete Institute (ACI), Eurocode 4 (EC 4), Architecture Institute of Japan (AIJ) and Chinese Design Code for Steel-Concrete Composite Structures (DL/T)).