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

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 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

Innovative porous ceramic matrices from inorganic polymer composites (IPCs): Microstructure and mechanical properties

The thermal performance of pegmatite-based geopolymer composites is investigated. Dense and compact matrix was prepared replacing metakaolin with pegmatite in the range of 70\u201385 wt% and activate with sodium hydroxide/sodium silicate solution in 1:1 vol ratio. The products of geopolymerization, cured at room temperature for 28 days, were heated at 100, 200, 400, 600, 800, 900, 1000 and 1100 \ub0C with 2 h soaking time. The high values of flexural strength (46\u201351 MPa) were observed at 1000 \ub0C as the consequences of low porosity (173 mm3/g) and water absorption (4.50\u20135.62%). The increase of the vitrification at 1100 \ub0C enhanced the liquid phase and develop porosities responsible for reduction of strength. The mechanical properties, microstructural evolution and pore size distribution were found to be influenced by the amount of fine powder of pegmatite (solid solution)

Effect of nanoclay on durability and mechanical properties of flax fabric reinforced geopolymer composites

The main concern of using natural fibres as reinforcement in geopolymer composites is the durability of the fibres. Geopolymers are alkaline in nature because of the alkaline solution that is required for activating the geopolymer reaction. The alkalinity of the matrix, however, is the key reason of the degradation of natural fibres. The purpose of this study is to determine the effect of nanoclay (NC) loading on the mechanical properties and durability of flax fabric (FF) reinforced geopolymer composites. The durability of composites after 4 and 32 weeks at ambient temperature is presented. The microstructure of geopolymer matrices was investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The results showed that the incorporation of NC has a positive impact on the physical properties, mechanical performance, and durability of FF reinforced geopolymer composites. The presence of NC has a positive impact through accelerating the geopolymerization, reducing the alkalinity of the system and increasing the geopolymer gel. © 2017 The Ceramic Society of Japan and the Korean Ceramic Society