The behavior of cold-formed steel geopolimeric composites

Geopolymer concrete-filled cold formed steel composite beams can exhibit high durability and adequate strength. The geopolymer concrete is used to manufacture the cold-formed steel tubular composite beam due to the significant advantages, such as greater in strength resisting capacity, higher-energy dissipation capacity, and more stiffness than the regular one. This paper reports an experimental investigation on the behavior of rectangular geopolymer concrete-filled cold-formed steel composite beams. In order to investigate the mechanical behavior (such as flexural, shear, and torsion) of geopolymer concrete-filled cold-formed steel tubular composite beams (GCFTBs), 48 beam samples were tested. The 16-GCFTBs and another 16-GCFTBs were tested under flexural and overhanging, respectively, which the 16-GCFTBs were tested under pure torsion. The relationships for load-displacement, torsional moment-rotation angle, energy dissipation capacity, ductility, and failure mode were analyzed. The test results showed that the increase in cross-sectional area and curing temperature had a significant effect on bending, shear and torsion behavior. Although the increase in the cross-section ratio (height/width) increased the bending moment capacity, it decreased the displacement capacity and caused a decrease in ductility. Curing conditions and cross-section ratio affected strength, displacement capacity, and experimental modulus of elasticity in both bending and shear tests. Increasing the cross-section ratio and curing temperature resulted in an increase in ductility. Contrary to bending test and shear test, curing temperature, and cross-section ratio increased both torsional moment strength and rotation angle in torsional moment tests.