Influence of mixing methods of nano silica on the microstructural and mechanical properties of flax fabric reinforced geopolymer composites

•Geopolymers are prepared using the wet-mix and dry-mix methods.•Nanosilica improves the microstructure of geopolymer.•Flexural and compressive strengths of samples are improved by nanosilica.•Samples prepared by dry-mixing have better physical and mechanical properties.

This paper presents the effects of two mixing methods of nanosilica on physical and mechanical properties of flyash-based geopolymer matrices containing nanosilica (NS) at 0.5, 1.0, 2.0, and 3.0 wt%. Comparison is made with conventional mechanical dry-mix of NS with fly-ash and wet-mix of NS in alkaline solutions. The influence of NS on the flexural toughness of flax fabric (FF) reinforced geopolymer nanocomposites has also been reported. Physical and microstructural properties are investigated using X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy. Results show that generally the addition of NS particles improves the microstructure and increases flexural and compressive strengths of geopolymer nanocomposites. However, samples prepared using the dry-mix approach demonstrate better physical and mechanical properties when compared to wet-mix samples.