Axial compressive behavior of GFRP-confined seawater coral aggregate concrete incorporating slag-based alkali-activated materials

Abstract

• A new type of GFRP-confined alkali-activated seawater coral aggregate concrete (AACAC) was developed. • Axial compression characteristics of GFRP-confined AACAC were investigated. • The FRP confinement was an effective method in enhancing the loading capacity and deformation of the concrete. • The ultimate strength and strain models for GFRP-confined AACAC were proposed. This paper investigated the experimental study on the axial compressive behavior of glass fiber-reinforced polymer (GFRP)-confined concrete, including cement-based seawater coral aggregate concrete (CAC) and slag-based alkali-activated seawater coral aggregate concrete (AACAC). The axial compression characteristics of the CAC and AACAC cylinders wrapped with different GFRP layers (i.e., 0, 2, 4, and 6 layers) were tested and analyzed. Experimental results showed that both CAC and AACAC specimens had a fairly similar failure pattern. The ultimate strain increment ratios are significantly higher than the ultimate strength ones, and AACAC exhibited a higher strain enhancement ratio than CAC. Moreover, the ultimate strength and axial strain gradually improved as the thickness of FRP increased. Approximately 2.88- and 5.79-times improvements in the ultimate axial strain were observed for the 6-ply CAC and AACAC specimens, respectively, compared with their un-confined companions, demonstrating that FRP jackets can effectively improve the axial deformation capacity of concrete cylinders. Additionally, experimental results were compared with some representative empirical models and then preliminary ultimate strength and strain models were proposed for GFRP-confined CAC and AACAC.