MARIA HOXHAJ, ILIRJANA BOCI, SIDORELA VISHKULLI, SONILA VITO, ANDI UZUNI
Abstract
The cement industry contributes significantly to global CO2 emissions, driving the need for sustainable alternatives in cement production. Calcined clay has emerged as a potential replacement for clinker in cement formulations. This study examines calcined clays sourced from different regions of central Albania for its suitability in cement production. The research includes chemical composition analysis, pozzolanic activity, and compressive strength testing of cement samples containing calcined clay. The results show that some of the clays exhibit pozzolanic properties, allowing for clinker replacement of up to 10%. Clays with kaolinite content above 40% in LC3 formulations can reach strengths comparable to CEM I 42.5R (>50 MPa), but the majority of local clays show lower reactivity and performance. However, large-scale adoption faces challenges due to high investment costs and economic feasibility, therefore practical clinker substitution rates are estimated at around 6–10%, balancing technical and economic considerations. Further research is needed to optimize the calcination process and evaluate the long-term performance of these regional clays.
Key words: Sustainable alternatives; calcined clay; clinker; compressive strength; pozzolanic activity.