Experimental study on the axial compression of GFRP-waste stone powder alkali-activated concrete-steel tube composite stub columns

In this paper, alkali-activated concrete prepared using waste stone powder is used to replace ordinary cement concrete to develop new glass fiber reinforced polymer (GFRP)-waste stone powder alkali-activated concretesteel tube composite columns. A total of 11 specimens were subjected to axial compression tests with respect to the GFRP tube thickness, concrete type, waste stone powder content, steel tube thickness and hollow ratio. The failure characteristics, load-displacement curves and bearing capacities of the specimens were analyzed. The results showed that the GFRP-waste stone powder alkali-activated concrete-steel tube composite stub columns (DSTC-AC) specimen exhibited three typical failure modes, and the specimen curve exhibited typical bilinear strengthening. The GFRP and steel tube have a significant effect on the mechanical properties and deformation of the specimens. GFRP restrains GFRP-ordinary concrete-steel tube composite stub columns (DSTC-C) and has a stronger restraining effect on ordinary concrete. A reasonable hollow ratio is beneficial for improving the efficiency of materials in DSTC-AC specimens. The DSTC-AC specimen with 50% waste stone powder has better axial compression performance. Based on the limit equilibrium theory, the bearing capacity calculation model of the specimen was established. The average ratio of the experimental value to the theoretical value is 0.96, and the COV is 0.14.