Axial Compressive Behavior of GFRP Tube Confined Seawater and Sea Sand Concrete Columns: Experimental Investigation and Theoretical Analysis

Abstract

Using seawater and sea sand concrete (SSC) can lower the emission of carbon dioxide in construction and alleviate the scarcity of river sand. To investigate the axial compressive behavior of glass fiber reinforced polymer (GFRP) tube confined SSC columns, 12 groups of GFRP tube confined SSC short columns were designed and tested. The results were analyzed and compared with those from tests on three groups of GFRP tube confined ordinary concrete short columns. The effects of GFRP tube wall thickness, SSC strength grade, and fly ash content were investigated in axial compressive experiments. The test results show that increasing the strength grade of concrete and the wall thickness of the GFRP tube can improve the ultimate bearing capacity of composite columns. Adding a certain amount of fly ash to the core concrete can improve the ultimate bearing capacity of the composite column, but the ultimate bearing capacity decreases when the amount of fly ash is too large. The compressive behavior of GFRP tube confined SSC columns is not very different from that of GFRP tube confined ordinary concrete columns. The stress and strain analysis was conducted considering the compressive stress in the GFRP tube, and most of the theoretical calculation results are consistent with the test values.