Experimental and probabilistic investigation on the durability of geopolymer concrete confined with fiber reinforced polymer

This study investigates the durability of confined geopolymer concrete with fiber-reinforced polymer and compares the results with ordinary Portland cement concrete (OPCC). Two hundred and seventy geopolymer concrete (GPC) specimens with different mix designs (fly ash- and granulated blast furnace slag(GBFS)-based GPC) were prepared and then wrapped with two different fiber-reinforced polymers (carbon and glass FRPs). For 12,960 hrs (eighteen months), the specimens were exposed to four different pHs (2.5, 7 (water), 7.25 (saltwater), 12.5). The reliability analysis was performed after modeling the compressive strength over time. Based on the results, the ductility of all specimens decreased 9 to 40 percent, depending on aggressive environments. The reduction of the compressive strength was up to 22% in an acidic environment. The compressive strength of the specimens increased 11 percent after being exposed to the alkaline solution. Overall, GPC had better durability than OPCC. The reliability analysis for durability for this study was compared with ACI 440-2R recommendations of aggressive environments. For the GFRP confined specimens, the probability of failure of limit state function for fly ash-based GPC under acidic, alkalic, salty water, and water conditions was 72.5, 33.3, 53.7, and 38.7 percent, respectively, and for GBFS-based GPC was 56.7, 22.7, 30.7, and 18.3, respectively. In most of the cases, the probability of failure of limit state function for CFRP confined specimens was less than GFRP confined.