20.500.12556/DKUM-93908 Enhancing strength and ▫$CO_2$▫ uptake in lignite-based fly ash geopolymer mortar through supercritical carbonation This study demonstrates the potential of supercritical CO₂ curing to enhance the performance and sustainability of lignite-based fly ash geopolymer mortar offering a promising approach to reducing CO₂ emissions in the construction industry while improving material properties. The research comprehensively compared conventional curing (GEO-REF) with supercritical CO₂ curing (GEO-CO₂), revealing that GEO-CO₂ samples exhibited higher compressive and flexural strengths, achieving peak performance almost immediately after curing. Supercritical CO₂ exposure resulted in enhanced carbonation, with a depth of up to 7.6 mm and a carbonation rate of up to 67 %. XRD confirmed phase changes due to CO₂ curing, with GEO-CO₂ showing additional calcium carbonate-calcite, calcium carbonate-aragonite, and calcium silicate hydroxide compared to GEO-REF. Nitrogen adsorption/desorption studies indicated larger pore diameters but a reduced BET surface area in GEO-CO₂ samples, suggesting structural changes due to CO₂ exposure. TGA analysis revealed that supercritical CO₂ curing reduced water retention and enhanced carbonation, resulting in increased CaCO₃ content and changes in Ca(OH)₂ levels. geopolymer fly ash carbonation CO2 fixation supercritical CO2 high pressure reactor geopolimeri karbonacija ogljikov dioksid superkritični ogljikov dioksid true false true Elsevier B.V. Angleški jezik Slovenski jezik https://www.sciencedirect.com/journal/the-journal-of-supercritical-fluids © 2025 The Author(s) Članek v reviji 2025-07-25 10:27:55 2025-07-25 10:27:55 2025-07-26 03:14:16 0000-00-00 00:00:00 2025 0 0 12 str. [article no.] 106695 Vol. 225 Nov. 2025 0000-00-00 Zaloznikova Objavljeno NiDoloceno 2025-01-16 2025-06-12 2025-06-18 66.02 241936131 10.1016/j.supflu.2025.106695 1872-8162 1-s2.0-S0896844625001822-main.pdf 1-s2.0-S0896844625001822-main.pdf 1 6931239501C6CB5B5EEC14BB2CB6CAED 3129f84f6143b8b77612bd087e0bf44cb706965bf7be55cb9c94e4f492a67853 8e3886b4-6931-11f0-b339-00155d000105 https://dk.um.si/Dokument.php?lang=slv&id=194152 Fakulteta za kemijo in kemijsko tehnologijo 0 0 0