Behaviour of Fly-Ash Geopolymer Mortar in Simulated Environments

Concrete and mortar usually found themselves in normal and harsh environments. The environment has great influence on the mechanical and durability behaviours of the concrete. In this study, fly ash was processed using circular economy concept and subsequently used as precursor for geopolymer mortar. The fly ash from Morupule power plant station has previously been characterized for its physical, chemical, and microstructural properties. Based on its suitability, the fresh and mechanical properties of the geopolymer mortar were carried out, and afterward, the durability behaviour is investigated in this study. The geopolymer mortar was formulated from the mixture of fly ash, sand and alkaline activators and cured thermally at 70°C. The behaviour of the geopolymer mortar in sulphuric acid solution, sodium sulphate solution, water absorption and fire resistance properties were simulated, and their loss in compressive strength and weight were determined. The laboratory experiment indicated that geopolymer mortars are highly resistant to sulphate attack, water absorption with moderate resistance against sulfuric acid and fire resistance. The effects of varying other parameters on the performance of concrete can be looked into in the future studies.