A Comparative Review of Comparative Study of Geopolymer Concrete and Conventional Concrete Under Acid Attack

This review examined the durability of fly ash–metakaolin geopolymer concrete and PPC concrete under sulfuric acid attack. The two systems differ in their binder composition and hardening mechanisms, which influence their chemical response and durability performance. Geopolymer concrete prepared using fly ash and metakaolin develops an aluminosilicate binding network through alkaline activation, without requiring cement as a binder. PPC concrete develops strength through cement hydration and pozzolanic reactions. Under sulfuric acid exposure, PPC concrete may undergo calcium leaching, gypsum formation, surface softening, and loss of material. Geopolymer concrete may experience alkali leaching, dealumination, and alteration of its binding gel. Published research suggests that suitably designed geopolymer systems can exhibit favorable acid resistance. However, the performance of fly ash–metakaolin geopolymer concrete cannot be assumed to be superior in every situation, and direct experimental comparison with PPC concrete is necessary. Compressive strength loss, strength retention, mass loss, visual deterioration, and microstructural changes should be evaluated together to provide a comprehensive assessment. Consistent curing and exposure conditions are also essential for reliable comparisons. Future research should focus on optimizing fly ash–metakaolin binder proportions, investigating long-term sulfuric acid exposure, and evaluating sustainability and cost. Such studies can help determine whether cement-free geopolymer concrete provides a technically and economically suitable alternative to PPC concrete in structures exposed to aggressive acidic environments.

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