Mechanical properties of geopolymers synthesized using basalt powder as a partial substitute for metakaolin

The utilization of volcanic powders, specifically basalt powders (BPs), as filler materials in the synthesis of geopolymers has gained significant attention in recent years. This study aims to investigate the potential application of basalt powders (BPs) in the synthesis process of geopolymers to develop more environmentally friendly structural materials. A comparative analysis was conducted, beginning with reference samples—geopolymers formulated exclusively from metakaolin and alkali-activated materials incorporating various types of BPs supplemented with differing amounts of metakaolin. The synthesis process was characterized by evaluating parameters such as volume density, compressive strength, and flexural strength. The most advantageous results, in addition to those achieved with metakaolin (MK), were observed for samples with a material ratio of 1:2:10 (NaOH: Na₂SiO₃:BP + MK) and a curing temperature of 20 °C, irrespective of the type of BP and the quantity of MK included. Furthermore, the inclusion of basalt resulted in a significant cost reduction of up to 80%, enhancing competitiveness against traditional Portland cement.