Constitutive Model of FRP Tube-Confined Alkali-Activated Slag Lightweight Aggregate Concrete Columns under Axial Compression

Abstract

Fiber reinforced polymer (FRP), as a novel type of composite material, has been extensively employed in structural strengthening and composite structures. The FRP tube-confined alkali-activated slag lightweight aggregate concrete column (FRP-AASLAC) can effectively improve the utilization rate of slag, reduce carbon emissions, reduce structural self-weight, and improve structural ductility. Therefore, the axial compressive properties of FRP-AASLAC were studied in this paper. The influences of the type of FRP, FRP thickness and the content of lightweight aggregate on the failure modes, bearing capacities, deformation properties and constitutive relationships of FRP-AASLAC were revealed. The results indicate that the constitutive relationships of FRP-AASLAC show double broken line patterns without obvious softening sections. The restraining effect of FRP on lightweight aggregate concrete is higher than that on ordinary concrete as lightweight aggregate concrete has lower strength and more easily undergoes lateral expansion under external loads. Models for compressive strength, peak compressive strain and constitutive relationship for FRP-AASLAC are proposed.