Transport-controlled multi-scale design of nano-clay and carbon fiber reinforced fly ash-based geopolymer composites: Enhanced mechanical and durability performance
Journal of Building Engineering, cilt.129, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 129
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.jobe.2026.116948
- Dergi Adı: Journal of Building Engineering
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC
- Anahtar Kelimeler: Carbon fiber reinforcement, Durability, Geopolymer composites, Multi-scale reinforcement, Nano-clay, Waste marble powder
- Atatürk Üniversitesi Adresli: Evet
Özet
This study comprehensively evaluates the mechanical and durability performance of nano-clay (NC) and carbon fiber (CF) reinforced fly ash-based geopolymer composites (GCs) incorporating 100% waste marble powder (WMP) as aggregate. NC (0–2 wt.%) and CF (0–0.75 vol%) were used to develop a multi-scale reinforcement system combining nano-scale densification and fiber-mediated crack control. The results show that compressive strength increased from 20.40 MPa to 36.30 MPa (+78%), while flexural strength improved from 1.91 MPa to 4.83 MPa (+153%), with optimum performance achieved at 1% NC and 0.75% CF. Beyond this level, strength decreased due to nanoparticle agglomeration and reduced matrix uniformity. Durability performance was significantly enhanced at the optimum NC content. Apparent porosity decreased to 7.44%, water absorption to 5.89%, and sorptivity to 0.95 kg/m2, indicating reduced pore connectivity and permeability. Under sulfate exposure (5% MgSO4, 120 days), strength loss was minimized to −4.51% with a weight loss of 4.63%, demonstrating improved resistance to chemical attack. Freeze–thaw resistance (100 cycles) showed the lowest strength loss of −11.42% and weight loss of 2.34%, attributed to reduced water ingress and effective crack-bridging by fibers. Thermal performance revealed strength gains of up to +23% at 200 °C, followed by severe degradation at higher temperatures, with losses approaching −80% at 700 °C due to gel decomposition and structural collapse. However, optimized mixtures exhibited relatively improved residual performance. Microstructural analyses (SEM/EDS) and XRD results collectively confirm that NC enhances geopolymerization by refining pore structure and increasing gel continuity, while CF improve fiber–matrix interfacial bonding and effectively restrict crack propagation. The optimum combination of 1% NC and CF produces a dense, low-permeability, and structurally integrated matrix, resulting in superior mechanical performance and enhanced resistance to chemical, thermal, and freeze–thaw degradation.