Abstract
Geopolymers are a modern class of construction materials that show significant potential for sustainable development, especially through the use of industrial wastes such as fly ash. This study investigated the effect of different oil additives on the properties of fly ash-based geopolymers, with particular emphasis on the use of both new and used oils. Test samples were prepared using class F fly ash and a 10-molar solution of sodium hydroxide and an aqueous solution of sodium silicate. Oil additives were added at 5%, 10% and 15% by weight. The physical and mechanical properties of the samples were assessed by measuring density, thermal conductivity, compressive and flexural strength, and by analyzing porosity and microstructure. The results showed that oil additives significantly affected the pore structure and mechanical properties of the geopolymers. Furthermore, the type and condition of the used oil determined the mechanical properties, including compressive and flexural strength. Research indicates the possibility of using oils as additives to geopolymers, which helps improve their physical properties and promotes sustainable development through recycling oil waste.