The use of waste from industrial activities is of particular importance for environmental protection. Fly ash has a high potential in the production of construction materials. In the present study, the use of fly ash in the production of geopolymer paste and the effect of Fe2O3, MgO and molarity of NaOH solution on the mechanical strength of geopolymer paste are presented. Samples resulting from the heat treatment of the geopolymer paste were subjected to mechanical tests and SEM, EDS and XRD analyses. Samples were obtained using 6 molar and 8 molar NaOH solution with and without the addition of Fe2O3 and MgO. Samples obtained using a 6 molar NaOH solution where Fe2O3 and MgO were added had higher mechanical strengths compared to the other samples.
Keywords: Fe2O3; MgO; compressive strength; geopolymer.