Performance optimization of silica fume–incorporated fly ash geopolymer mortars: mechanical, thermal, microstructural and environmental assessment
European Journal of Environmental and Civil Engineering, cilt.30, sa.1, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 30 Sayı: 1
- Basım Tarihi: 2026
- Doi Numarası: 10.1080/19648189.2026.2665283
- Dergi Adı: European Journal of Environmental and Civil Engineering
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, ICONDA Bibliographic, INSPEC
- Anahtar Kelimeler: elevated temperature, Fly ash, life cycle assessment, microstructure, silica fume
- Erciyes Üniversitesi Adresli: Evet
Özet
This study investigated the effects of silica fume substitution on the mechanical, microstructural, and environmental performance of fly ash-based geopolymer mortars cured at 60 °C and 90 °C. Silica fume replaced fly ash at levels between 2% and 10%, and the mixtures were evaluated for unit weight, water absorption, porosity, capillary water absorption, abrasion resistance, high-temperature resistance, thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), and life cycle assessment (LCA) analyses. The results indicated that incorporating 2–4% silica fume under 60 °C curing provided the highest compressive and flexural strengths while maintaining low porosity and water absorption. Higher replacement ratios led to matrix deterioration and increased porosity. Although curing at 90 °C accelerated early-age strength development, prolonged exposure caused moisture loss and microcrack formation, resulting in unstable strength behaviour. Mixtures containing 2% silica fume exhibited the best capillary water absorption and abrasion resistance. Under elevated temperatures, some mixtures showed strength gains at 300 °C, followed by reductions at 600 °C and partial recovery at 900 °C due to sintering effects. FESEM and TGA confirmed that lower silica contents promoted a denser gel structure. LCA results demonstrated that geopolymer mortars offer environmental benefits in terms of global warming potential. Overall, a 2% silica fume replacement provided the most balanced mechanical, microstructural, and environmental performance.