Rice Husk Ash as a Silica Source in a Geopolymer Formulation

Heo, Un Haeng; Sankar, Kaushik; Kriven, Waltraud M.; Musil, Sean S.

doi:10.1002/9781119040293.ch7

Cited by 19 publications

(19 citation statements)

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“…Sodium-based geopolymer reinforced with 30 wt.% untreated jute weave resulted in 20.5 MPa four-point flexure strength 11 . Potassium-based geopolymer reinforced with 6.4 wt.% rice stem yielded 18 MPa three-point flexure strength 12 . Potassium-based geopolymer reinforced with 30 wt.% alkali-treated fique fibers yielded 11 MPa four-point flexure strength 13 .…”

Section: Introductionmentioning

confidence: 99%

Mixed Alkali Regional Metakaolin‐Based Geopolymer

SáRibeiro

Sankar

et al. 2017

Ceramic Engineering and Science Proceedings

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In pursuit of sustainable construction, regional natural materials can be used as a base for geopolymer processing. For higher strength achievement, this study uses mixed potassium-sodium geopolymer. Geopolymer was synthesized using metakaolin produced from kaolinite extracted from Amazonian soil, and microscopically compared to a commercial, highly reactive, metakaolin-based geopolymer. Amazonian kaolin was converted into metakaolin by calcination up to 700 °C. X-ray diffraction (XRD) analysis showed the resulting amorphous metakaolin to be 76% pure, with 24% crystalline quartz impurity. Four-point flexural and compressive strength testings of the geopolymer were carried out according to ASTM standards. Scanning electron microscopy was used to investigate the microstructure and the Si/Al ratio. In addition, XRD was used to confirm the formation of geopolymer.

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Section: Introductionmentioning

confidence: 99%

Mixed Alkali Regional Metakaolin‐Based Geopolymer

SáRibeiro

Sankar

et al. 2017

Ceramic Engineering and Science Proceedings

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“…Geopolymers can be tailored to be a high‐strength, environmentally friendly, structural material that can be made using local resources . In addition to the mineral reserves containing aluminosilicates, there are many industrial processes that generate slag, fly ash, and other byproducts as sources of aluminosilicates, so that the raw material for exploitation of this technology is abundant.…”

Section: Introductionmentioning

confidence: 99%

Potassium‐Based Geopolymer Composites Reinforced with Chopped Bamboo Fibers

Sankar

Ribeiro

et al. 2016

J. Am. Ceram. Soc.

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Bamboo is a fast-growing, readily available natural material with tensile specific strength equivalent to that of steel (250-625 MPa/g/cm 3 ). In the pursuit of sustainable construction materials, a composite was made with potassium polysialate siloxo geopolymer as the matrix and randomly oriented chopped bamboo fibers (Guadua angustifolia) from the Amazon region as the reinforcement. Four-point flexural strength testing of the geopolymer composite reinforced with bamboo fibers was carried out according to ASTM standard C78/C78M-10 e1. Potassiumbased metakaolin geopolymer reinforced with 5 wt% (8 vol%) untreated bamboo fibers yielded 7.5 MPa four-point flexural strength. Scanning electron microscopy and optical microscopy were used to investigate the microstructure. In addition, X-ray diffraction was used to confirm the formation of geopolymer. the relationships between composition, processing, microstructure, and the properties of metakaolin-based geopolymers (MKGPs) and found that the best compressive strength is obtained when the Si:Al molar ratio is 2:1 in geopolymers. When compared to ordinary portland cement (OPC), geopolymers have faster setting time and lower density. The mechanical properties of geopolymers are superior to portland cement in general, but are influenced by the contents of the liquid phase in the mixture, the curing temperature, and the final porosity of the body. 5 The energy required to produce geopolymer is considerably lower than that required for OPC. The extent of reduction in energy depends upon the raw materials used to make the geopolymer. 7 They are processed as a liquid enabling them to be cast into any shape and cured at ambient or slightly elevated temperatures. However, like ceramics, pure geopolymers are brittle and are weak in tension. Their failure is catastrophic with very little warning signal. On the other hand, they can

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“…The curves of S 2 and S 4 resembled that of S 1 except for the first exothermic decomposition, which was low in agreement with the low C% content (Table 1). Later on, over 800 1C, temperature behaviour might be defined by the decomposition of HA lattice and its conversion to beta-TCP, accompanied with water loss [9,31]. The decomposition of HA to TCP at high temperature has been confirmed by XRD analysis (data not shown), which qualitatively estimated the relative volume % amount of the two main phases HA/TCP equal to 70/25 at 900 1C and 10/80 at 1200 1C.…”

Section: Thermal Analysismentioning

confidence: 85%

“…Alternatively, calcium-phosphate meat and bone meal ashes have been proposed as a valid alternative to inert silica sand in cementitious mortars, as they generally show physical and mechanical properties comparable to that of siliceous fine fraction used in mortars [6,7]. Few other studies investigated the role of amorphous silica derived from vegetal biomass such as rice husk, both in cementitious and geopolymer binders [8,9] However until now, besides few investigations that focused on their reuse as Portland cement (OPC) mixture additions, to the author's knowledge calcium-phosphate biomass ashes have never been considered as a potential raw material for geopolymers, the low temperature hardened ceramic-like material.…”

Section: Introductionmentioning

confidence: 99%