Characterization of flax fabric reinforced nano-clay geopolymer composites

Geopolymer composites reinforced with flax fabrics (FF) and nanoclay platelets are synthesised and studied in terms of physical and mechanical properties. X-Ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning Electron Microscope (SEM) techniques are used for phase and microstructure characterisation. The nanoclay platelets are added to reinforce the geopolymer matrices at 1.0%, 2.0%, and 3.0% by weight. It is found that 2.0 wt.% nanoclay enhances the density, decreases the porosity and subsequently improves the flexural strength and toughness. The microstructural analysis results indicate that the nanoclay behaves not only as a filler to improve the microstructure of the binder, but also as an activator to support the geopolymeric reaction producing higher content of geopolymer gel. This enhances the adhesion between geopolymer matrix and flax fibres, which improves the mechanical properties of the geopolymer nanocomposites reinforced with flax fabrics

Characterization, reactivity and rheological behaviour of metakaolin and Meta-halloysite based geopolymer binders

The type of aluminosilicate precursor used in the synthesis of geopolymer binders plays a huge role in the resulting performance. Thus, it is critical to understand the properties of precursors and how they influence the corresponding performance of geopolymer binders. In this study, metakaolin and meta halloysite are used as the aluminosilicate precursor in the synthesis of geopolymer binders. These precursors are obtained locally in order to propel the sustainable development and application of geopolymers. The precursors were characterized and the corresponding influence on the reactivity, rheology and setting times of geopolymers was investigated. In addition to the influence of precursor type on the properties of the geopolymers, the effect of two silica moduli (i.e. 1.3 and 1.5) was also evaluated. The results from this study indicated that increasing the activator silica modulus from 1.3 to 1.5 extended the setting times and increased the stress strain of the geopolymer binders. Characterization of the precursors indicated that metakaolin has a higher amorphous content compared to that of meta halloysite. However, the finer particles of meta halloysite embodied it with the ability to participate in a faster geopolymerization and result in more formation of activation products

Effect of nano-clay on mechanical and thermal properties of geopolymer

AbstractThe effect of nano-clay platelets (Cloisite 30B) on the mechanical and thermal properties of fly ash geopolymer has been investigated in this paper. The nano-clay platelets are added to reinforce the geopolymer at loadings of 1.0%, 2.0%, and 3.0% by weight. The phase composition and microstructure of geopolymer nano-composites are also investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) techniques. Results show that the mechanical properties of geopolymer nano-composites are improved due to addition of nano-clay. It is found that the addition of 2.0wt% nano-clay decreases the porosity and increases the nano-composite's resistance to water absorption significantly. The optimum 2.0wt% nano-clay addition exhibited the highest flexural and compressive strengths, flexural modulus and hardness. The microstructural analysis results indicate that the nano-clay behaves not only as a filler to improve the microstructure, but also as an activator to facilitate the geopolymeric reaction. The geopolymer nano-composite also exhibited better thermal stability than its counterpart pure geopolymer

Synthesis and mechanical properties of flax fabric reinforced geopolymer composites

Geopolymer composites reinforced with different layers of woven flax fabric are fabricated using lay- up technique. Mechanical properties, such as flexural strength, flexural modulus and fracture toughness of geopolymer composites reinforced with 2.4, 3 and 4.1 wt% flax fibres are studied. The fracture surfaces of the composites are also examined using scanning electron microscopy. The results show that all the mechanical properties of the composites are improved by increasing the flax fibre contents. It is also found that the mechanical properties of flax fabric reinforced geopolymer composites are superior to pure geopolymer matrix. Micro-structural analysis of fracture surface of the composites indicated evidence of various toughening mechanisms by flax fabrics in the composites

Effect of water absorption on the mechanical properties of cotton fabric-reinforced geopolymer composites

AbstractCotton fabric (CF) reinforced geopolymer composites are fabricated with fibre loadings of 4.5, 6.2 and 8.3wt%. Results show that flexural strength, flexural modulus, impact strength, hardness and fracture toughness are increased as the fibre content increased. The ultimate mechanical properties were achieved with a fibre content of 8.3wt%. The effect of water absorption on mechanical and physical properties of CF reinforced geopolymer composites is also investigated. The magnitude of maximum water uptake and diffusion coefficient is increased with an increase in fibre content. Flexural strength, modulus, impact strength, hardness and fracture toughness values are decreased as a result of water absorption. Scanning electron microscopy (SEM) is used to characterise the microstructure and failure mechanisms of dry and wet cotton fibre reinforced geopolymer composites

Effect of Nanosilica on mechanical properties and microstructure of PVA Fiber-Reinforced Geopolymer Composite (PVA-FRGC)

This paper presents the effects of various nanosilica (NS) contents on the mechanical properties of polyvinyl alcohol (PVA) fiber-reinforced geopolymer composites (PVA-FRGC). Microstructure analysis with X-ray diffraction (XRD) and scanning electron microscopy (SEM) was used to characterize the geopolymer composites. The results showed that the mechanical properties in terms of compressive strength, impact strength, and flexural behavior were improved due to the addition of NS to the PVA-FRGC. The optimum NS content was 1.0 to 2.0 wt%, which exhibited highest improvement in the above mechanical properties. Microstructure analysis showed that the addition of NS up to an optimum level densified the microstructure of the matrix as well as the PVA fiber-geopolymer matrix interface

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

© 2016 Elsevier LtdThis 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