Optimization and performance assessment of nano-Al₂O₃ modified basalt fiber reinforced alkali-activated slag composites containing waste marble powder
Construction and Building Materials, cilt.541, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 541
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.conbuildmat.2026.147809
- Dergi Adı: Construction and Building Materials
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
- Anahtar Kelimeler: Alkali-activated slag, Basalt fiber, Durability performance, Microstructure, Nano-Al₂O₃, Waste marble powder
- Atatürk Üniversitesi Adresli: Evet
Özet
This study investigates the synergistic effects of nano-aluminum oxide (n-Al₂O₃) and basalt fiber (BF) reinforcement on the mechanical performance, durability, thermal resistance, and microstructural evolution of alkali-activated slag (AAS) composites incorporating waste marble powder (WMP) as a full replacement for natural fine aggregate. Ground granulated blast-furnace slag (GBFS) was used as the primary aluminosilicate precursor, while n-Al₂O₃ was introduced at dosages of 0–1.0 wt% as a partial replacement of GBFS and BF was incorporated at 0–1.0 vol%. All mixtures were thermally cured at 75 °C for 8 h to accelerate geopolymerization. Moderate n-Al₂O₃ contents (0.25–0.50 wt%) improved the physical and mechanical performance of the composites, increasing compressive strength from 19.1 MPa to 30.3 MPa and flexural strength from 2.75 MPa to 3.54 MPa, while reducing apparent porosity from 9.87% to 8.09%, water absorption from 8.24% to 6.65%, and sorptivity from 1.89 to 1.15 kg/m². The incorporation of BF further enhanced the overall performance, with the optimum mixture obtained at 0.5 vol% BF combined with 0.5 wt% n-Al₂O₃. At this optimum combination, compressive and flexural strengths reached 37.5 MPa and 4.77 MPa, corresponding to increases of approximately 95% and 73%, respectively, compared with the reference mixture, while porosity and sorptivity were reduced by about 26% and 46%. Durability results demonstrated composition-dependent behavior. The 1.0 wt% n-Al₂O₃ mixture (0BA10) exhibited the highest sulfate resistance, with only 0.66% strength loss after 120 days of exposure to a 5 wt% MgSO₄ solution, compared with 20.0% for the reference mixture. The optimized mixture (50BA50) showed the lowest freeze-thaw strength loss (30.8%) after 60 freeze-thaw cycles, whereas the reference mixture lost 70.4%. Thermal exposure increased compressive strength by up to 15.2% after exposure to 200 °C, while the lowest strength losses at 400 °C (11.35%) and 600 °C (36.30%) were achieved by 0BA25. SEM and XRD analyses indicated comparatively denser matrix regions and improved fiber–matrix contact in the optimized mixtures, consistent with the measured engineering performance.