Akademik Veri Yönetim Sistemi
Construction and Building Materials, cilt.505, 2025 (SCI-Expanded, Scopus)
The growing environmental concerns and high CO2 emissions associated with Portland cement production necessitate the development of alternative, sustainable binders. This study examines the feasibility of producing geopolymer mortars incorporating recycled concrete aggregate (RCA) to replace natural river sand partially. Fly ash and slag were used as binders activated with sodium hydroxide and sodium metasilicate. RCA was incorporated at 10–50 % replacement levels, and the mixtures were evaluated for their physical, mechanical, high-temperature, microstructural, and cradle-to-gate life cycle assessment (LCA) properties. The results indicated that RCA incorporation caused only minor variations in unit weight. The mechanical performance of fly ash-based mixtures improved up to moderate RCA replacement levels, while higher substitutions showed more limited gains. In slag-based systems, RCA contributed positively under specific curing conditions. Fly ash mortars exhibited better thermal stability, with partial strength recovery at 900°C, whereas slag mortars showed a continuous decline in strength. LCA findings revealed that RCA use reduced the overall environmental impacts compared with Portland cement mortars, although the environmental burden of alkaline activators remained significant. The study demonstrates that integrating RCA into geopolymer mortars can contribute to sustainability when applied at appropriate replacement ratios and under optimized curing conditions.