Synthesis and mechanical properties of eco-friendly geopolymers obtained from waste materials

This paper investigates the synthesis and mechanical properties of geopolymers obtained from industrial waste - fly ash and granulated blast furnace slag - with the aim of developing environmentally friendly and sustainable construction materials. The raw materials were activated with alkaline solutions of water glass and 12M NaOH in a 1:2 ratio. The ratio of alkali to precursor (fly ash, slag and quartz sand) was 1:1. The dependence of the compressive strength on the addition of slag was tested for geopolymer pastes (C), and geopolymer mortars (P) based on fly ash and quartz sand, both with and without granulated blast furnace slag. The results show that adding up to 20% slag does not significantly affect the compressive strength of the geopolymer. The compressive strengths of geo ratio polymer pastes are 30-50% higher than those of geopolymer mortars. However, the compressive strengths of both geopolymer pastes and mortars after 2 and 7 days are twice as high as the standard values of compressive strengths of cement mortars after 2 and 7 days according to EN 197-1. Chemical analysis (XRF) confirmed the presence of high content of SiO2, Al2O3 and CaO in the starting materials, which contributes to the formation of a strong geopolymer structure. The obtained results indicate the potential of geopolymers as a sustainable and environmentally friendly alternative to conventional binders in construction.