Comparative Study Between Alkali-Activated Mortar and Conventional Mortar Towards Sulphuric Acid

The alkali-activated concrete (AAC) is an ecofriendly alternative to ordinary Portland cement (OPC) concrete. AAC reduces carbon emissions by the usage of aluminosilicate materials instead of OPC. The buildings and other concrete structures can be exposed to acids throughout its service life, especially in marine buildings, factories, agricultural, and sewage components. This study aims to the comparison of resistance of AAC and conventional mortar towards sulphuric acid (H₂SO₄) attack. The materials used for the preparation of AAC mortar specimens are cementitious components and alkaline activators. The cementitious components are GGBS and fly ash as the binding material of ratio 1:9. The alkaline activators used are sodium hydroxide (NaOH) solution of 8 M and sodium silicate (Na₂SiO₃) solution, which has a ratio of 1:2.5. Sulphuric acid of 98% assay is used for preparation of the 5% acid solution. Totally, 9 cubes for AAC and 9 cubes for OPC mortar specimens of size 7 cm × 7 cm × 7 cm were prepared and the specimens were shifted to H₂SO₄, and the changes have to be observed by visual appearance, mass loss, volume change, pH value, and compressive strength test at the age of 1-month duration. The results suggest that alkali-activated mortar specimens show better performance than OPC mortar specimens.