Axial behavior of slender steel tube filled with steel-fiber-reinforced recycled aggregate concrete

The increasing annual output of construction waste brings severe space decreasing, resource shortage and environment depravation. Cyclic utilizing the recycled coarse aggregate (RCA) is inevitable. This paper uses the steel-fiber-reinforced recycled aggregate concrete (SRAC) as filling to manufacture CFST columns, called SRACFST columns. A comprehensive study for the axial behavior of 39 slender SRACFST columns is presented. The experimental parameters are the slenderness ratio (lambda), steel fiber volume (v), quality replacement rate of regenerated aggregate (RAR), concrete strength grade and diameter-thickness ratio of steel tube (D/t). Failure mode, axial load-lateral deflection behavior, axial load-strain response and ultimate capacity are researched. The results show that slender SRACFST columns present the similar compressive behavior to the common slender CFST columns. The defect of RAC can be compensated by the confinement effect of steel tube and the bridging effect of steel fibers. With the rise in slender ratio. the confinement of steel tube and steel fibers is faded out. (C) 2019 Elsevier Ltd. All rights reserved.