Investigation of Natural Clays as Precursor for Geopolymers – A Preliminary Study Case

Concrete is responsible for 8–10% of total anthropogenic CO₂ emissions, with cement production accounting for over 60% of this contribution. Considering this environmental impact, the integration of sustainable and alternative materials as replacements for cement represents a promising strategy for emission reduction. Alkali-activated materials and/or geopolymers can be used as an alternative construction material and are formed by activating aluminosilicates such as fly ash, granulated blast furnace slag, and/or clays with alkaline solutions. The selection of precursors for geopolymer synthesis is strictly related to their local availability. Among these, activated clays have gained considerable attention, offering great potential for geopolymer production due to their widespread availability and composition. Albania has a great potential due to the weathering conditions, but very limited information is available. In this preliminary study case, different clays were collected from different areas across Albania and investigated for their reactivity and suitability as precursors for geopolymers after thermal treatment. These clays were subject to characterization, and their reactivity was assessed according to R3-bound water methods. Calcination of clays was performed at temperatures of 650 and 750 ℃ for 1 h. The results indicated that calcined clays from Albania can have potential to be suitable source materials in geopolymerization reactions and/or as supplementary cementitious materials.