Compressive test of GFRP-recycled aggregate concrete-steel tubular long columns

In order to alleviate the problem of growing construction waste and utilize the favorable material properties of fibre-reinforced polymer (FRP), a novel form of composites, FRP-recycled aggregate concrete-steel columns (FRSCs), was proposed based on hybrid FRP-concrete-steel double-skin tubular columns (DSTCs). The composite of FRSC consists an outer FRP tube and an inner steel tube with an annular area of recycled aggregate concrete (RAC) filled between both tubes. To further investigate the compressive behavior of these composites, an experiment of Glass FRP-RAC-steel tubular long columns (FRSLCs) was performed subjected to monotonic axial compression. Three parameters were designed in the test, which are the recycled coarse aggregate (RCA) replacement ratio, the slenderness ratio and the cross-section loading method. The influence of these parameters was analyzed on the bearing capacity, lateral deflection performance and the load-strain relationship of FRSLCs. The test results show that FRSLCs have good bearing capacity and excellent ductility. Two models for DSTCs were transformed to apply in FRSLCs, which has found that Lu's model (2013) is appropriate to predict the ultimate bearing capacity of FRSLCs under the whole area loading.