Synthesis and Characterization of Coal Fly Ash-based Foamed Geopolymer

Nyale, Sammy M.; Babajide, Omotola; Birch, Grant D.; Böke, Nuran; Petrik, Leslie

doi:10.1016/j.proenv.2013.04.098

Cited by 85 publications

(46 citation statements)

References 24 publications

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“…Fly ash showed main broad absorption band at ~960 cm −1 , which corresponding to the asymmetrical stretching vibration of Si-O-Si and Si-O-Al. This band shifted to lower wavenumber (~950 cm −1 ) after the geopolymerization reaction33. This inferred the incorporation of Al atoms in the silicate geopolymer network and increasing non-bridging oxygen in structure3247.…”

Section: Resultsmentioning

confidence: 92%

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Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

Cheng-Yong

Yun-Ming

Abdullah

et al. 2017

Sci Rep

114

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This paper presents a comparative study of the characteristic of unfoamed and foamed geopolymers after exposure to elevated temperatures (200–800 °C). Unfoamed geopolymers were produced with Class F fly ash and sodium hydroxide and liquid sodium silicate. Porous geopolymers were prepared by foaming with hydrogen peroxide. Unfoamed geopolymers possessed excellent strength of 44.2 MPa and degraded 34% to 15 MPa in foamed geopolymers. The strength of unfoamed geopolymers decreased to 5 MPa with increasing temperature up to 800 °C. Foamed geopolymers behaved differently whereby they deteriorated to 3 MPa at 400 °C and increased up to 11 MPa at 800 °C. Even so, the geopolymers could withstand high temperature without any disintegration and spalling up to 800 °C. The formation of crystalline phases at higher temperature was observed deteriorating the strength of unfoamed geopolymers but enhance the strength of foamed geopolymers. In comparison, foamed geopolymer had better thermal resistance than unfoamed geopolymers as pores provide rooms to counteract the internal damage.

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Section: Resultsmentioning

confidence: 92%

“…The foam could be introduced through air bubbles20 or endogeneous gas generation (e.g. aluminium powder29, hydrogen peroxide3031 or sodium hypochlorite3233). In this study, hydrogen peroxide was used as the gas-forming agent.…”

mentioning

confidence: 99%

Thermal Resistance Variations of Fly Ash Geopolymers: Foaming Responses

Cheng-Yong

Yun-Ming

Abdullah

et al. 2017

Sci Rep

114

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“…The length of time the mixture was left in a slurry form before being placed in the oven affect the porosity of foamed geopolymers. Geopolymer formation shows Si-O and Al-O stretching vibrations [18].…”

Section: Geopolymer Pastementioning

confidence: 99%

Characterization and compressive strength of fly ash based-geopolymer paste

et al. 2018

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Abstract. Fly ash is a by-product obtained from coal combustion process. Some of the utilization of fly ash is to produce geopolymer products which have high compressive strength, fire, chemical resistance. This paper proposes fly ash from unit 1-7 Suralaya Power Plant Indonesia. The aims of this study are to obtain characterization of fly ash and mechanical properties of geopolymer paste based on variations of the alkali activator ratio. The method was based on previous research and laboratory investigation. XRF and compressive strength were analysed in this study. Alkali activator was obtained from NaOH and Na2SiO3 mixture. The ratio of Na2SiO3 to NaOH was in the range of 0.5-2.5. Geopolymer paste was casted in acrylic cylinders with a diameter of 2 cm and a height of 4 cm. The curing was conducted at room temperature until the day for the compressive strength test at 28 days. The result showed that the fly ash is classified as F class. Increasing the alkali activator ratio influenced the strength. The best composition of geopolymer paste is made with NaOH 8M, and the mass ratio of Na2SiO3 to NaOH is 2.5. This composition produced compressive strength of 98.6 MPa.

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“…The beneficiation of South African FA after it has been put through a process of air classification, electrostatic recovery and/or density separation has been described before [1], and specific size fractions of FA, with specific physical and chemical properties, may be used in suitable applications. The country's research and development involving FA includes its application in building and construction as cement extender and into lightweight aggregates [4], environmental rehabilitation in the form of counteracting acid mine drainage, wastewater treatment, and toxic element immobilization by zeolites [5][6][7], mine backfilling, the recovery of alumina [8,9], production of geopolymers [10,11] and hydrotalcites [12], soil amelioration [13], refractories and bricks, road stabilization, CO 2 capture [14], and as a processing aid and functional filler in polymers [15].…”

Section: Introductionmentioning

confidence: 99%