Akademik Veri Yönetim Sistemi
Materials, cilt.19, sa.1, 2026 (SCI-Expanded, Scopus)
Highlights: What are the main findings? This study compares fly-ash-based geopolymers reinforced with short glass fibers and flax fibers, as well as hybrid fiber reinforcement, which was not previously studied in the literature. Results show that 1 wt% glass fibers effectively enhance compressive performance and matrix densification. What are the implications of the main findings? The fiber addition at the tested dosages does not improve flexural strength. Optimizing fiber content/dispersion and interfacial treatment is recommended. This study compares fly-ash-based geopolymers reinforced with short glass fibers (GF) or flax fibers (FF). Four mixes were produced: reference (FA), 1 wt% GF, 1 wt% FF, and a hybrid (0.5 wt% GF + 0.5 wt% FF). These compositions were cast into prism and cube molds, cured at 75 °C for 24 h, and tested after 28 days. Mechanical testing included compressive strength and three-point bending, phase composition by XRD, and microstructure by optical and SEM microscopy. The GF composite showed the highest compressive strength (mean up to ~28–34 MPa versus ~17 MPa for the reference), while FF gave intermediate values (~11–22 MPa). During bending, the reference achieved the highest flexural strength (~5.5 MPa); fiber-reinforced mixes ranged from ~2.9 to 4.4 MPa. XRD indicated a typical amorphous aluminosilicate gel over crystalline remnants; SEM/optical observations revealed a denser, more compact matrix with fewer voids for GF systems, whereas FF and hybrid mixes exhibited localized porosity and fiber pull-out imprints affecting crack initiation/propagation. Overall, 1 wt% GF effectively enhances compressive performance and matrix densification, while fiber addition at the tested dosages does not improve flexural strength; optimizing fiber content/dispersion and interfacial treatment is recommended.