Experimental Study on Acid Resistance of Geopolymer Concrete Incorporating Fly Ash and GGBS: Towards Low-Carbon and Sustainable Construction

This experiment investigated the mechanical performance and acid resistance (when subjected to 28 days of exposure to sulfuric and nitric acid of five percent) of ambient-cured geopolymer concrete. Geopolymer concrete (GPC)—which is produced by using industrial by-products, including fly ash and ground granulated blast furnace slag (GGBS)—is a low-carbon and strong substitute of Ordinary Portland Cement (OPC). This experiment examines the mechanical and acid-resisting properties of ambient GPC with different GGBS (10, 30, and 50 percent) contents. The compressive, tensile, and flexural strengths were measured at 7, 14, and 28 days, and durability was measured under an exposure of 5% sulfuric and nitric acids. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that gypsum and ettringite were formed by sulfuric acid that weakened the structure, whereas surface decalcification was mostly caused by nitric acid. Mixes with a high fly ash content had more amorphous structures and better acid resistance, whereas those having high GGBS contents had high early strength because of high densities of the C–A–S–H gel. The findings indicate a strength–durability trade-off, which can be used to control the optimized mix design to produce sustainable and long-term infrastructure.