Understanding the relationship between geopolymer composition, microstructure and mechanical properties

Duxson, Peter; Provis, John L.; Lukey, Grant C.; Mallicoat, Seth W.; Kriven, Waltraud M.; Deventer, J.S.J. van

doi:10.1016/j.colsurfa.2005.06.060

Cited by 1,479 publications

(875 citation statements)

References 33 publications

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“…5 clearly demon strate an increase in their number (identified by white arrows) when the WG content rises, suggesting a lower degree of the geopolymeric reaction and, therefore, a worse mechanical perfor mance. Similar findings have been reported for WG containing geopolymers (Hao et al, 2013;Lin et al, 2012), and for MK based geopolymers which were produced with distinct Si/Al ratios (Duxson et al, 2005). Khale and Chaudhary (2007) suggested that the Si/Al ratio must lie between 3.3 and 4.5 in order to form strong geopolymeric prod ucts.…”

Section: Geopolymers Characterizationsupporting

confidence: 72%

Waste glass from end-of-life fluorescent lamps as raw material in geopolymers

et al. 2016

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a b s t r a c tNowadays the stunning volume of generated wastes, the exhaustion of raw materials, and the disturbing greenhouse gases emission levels show that a paradigm shift is mandatory. In this context, the possibility of using wastes instead of virgin raw materials can mitigate the environmental problems related to wastes, while reducing the consumption of the Earth's natural resources. This innovative work reports the incorporation of unexplored waste glass coming from end of life fluorescent lamps into geopolymers.The influence of the waste glass incorporation level, NaOH molarity and curing conditions on the microstructure, physical and mechanical properties of the geopolymers was evaluated. Results demon strate that curing conditions are the most influential factor on the geopolymer characteristics, while the NaOH molarity is less important. Geopolymers containing 37.5% (wt) waste glass were successfully produced, showing compressive strength of 14 MPa (after 28 days of curing), suggesting the possibility of their use in non structural applications.Porous waste based geopolymers for novel applications were also fabricated.

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Section: Geopolymers Characterizationsupporting

confidence: 72%

Waste glass from end-of-life fluorescent lamps as raw material in geopolymers

et al. 2016

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“…The presence of anhydrous silicates in both spectra (signal at −72 ppm) supported the premise that C-S-H gel was not the only binder forming in systems C and D. The gel did, however, form part of both binders, since some of the clinker disappeared (was hydrated) in these systems: note the difference in the signal at −72 ppm between spectra B and C on the one hand and spectrum A on the other. The presence of low intensity signals at −90, −95 and −102 ppm in spectra C and D was also significant, since in prior studies (37,40,81,87,88) these signals were associated with N-A-S-H gel and attributed to Q 4 units with 3, 2 or 1 aluminium atoms.…”

Section: Co-precipitation Of Cementitious Gels: C-s-h + N-a-s-hmentioning

confidence: 96%

“…Studies conducted by a number of authors (84)(85)(86)(87)(88)(89)(90)(91)(92)(93)(94) showed that both the curing temperature and type of activator impact reaction kinetics, with the degree of reaction rising with curing temperature. In addition, the nature of the products generated (N-A-S-H gel-like and zeolite precipitates) in of aluminosilicate activation varies with curing time and temperature.…”

Section: Fundamentals Of Alkaline Activation In Lowcalcium Systems:[(mentioning

confidence: 99%

A review on alkaline activation: new analytical perspectives

et al. 2014

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For many years now the idea of including alkalis in a Portland cement matrix has been regarded as a daft or inexcusably erroneous proposition: despite its absurdity, that opinion has been widely accepted as a basic premise by the scientific and technical community working in the area of the chemistry of cement. In 1957 Glukhovsky proposed a working hypothesis in which he established a close relationship between alkalis and cementitious materials. That hypothesis has become consolidated and has served as a basis for developing a new type of binders, initially called "alkaline cements". The present paper reviews the most significant theoretical interpretations of the role played by alkalis in the formation of the "stony" structure of cement. It ends with a broad overview of the versatility of this type of materials for industrial applications and a discussion of the possibility of building on the existing legislation to meet the need for the future regulation of alkaline cement and concrete manufacture. RESUMEN: Activación alcalina: Revisión y nuevas perspectivas de análisis.Hace algunos años, la sola idea de la presencia de álcalis en una matriz de cemento Portland se consideraba casi como una aberración, o como un error imperdonable; convirtiéndose en un postulado básico (absurdo) ampliamente aceptado por la comunidad científica y técnica vinculada a la química de los cementos. En 1957 Glukhovsky propuso una hipótesis en la que se establecía una estrecha relación entre los álcalis y los materiales cementantes. Hoy día nadie duda de que dicha hipótesis ha servido de base para el desarrollo de una nueva clase de materiales cementantes: "cementos alcalinos". En el presente trabajo se hace una revisión sobre los aspectos teóricos más relevantes del papel de los álcalis en la formación de estos conglomerantes. También se da una visión genérica de su versatilidad, desarrollo industrial y estado de la normativa actual para regular en el futuro la fabricación de cementos y hormigones alcalinos.

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“…In combination with the results obtained through high temperature in-situ measurements [34,35,37], this can be divided into three sub-regions: in region I (100-300°C), a large shrinkage occurs mainly due to pore water and region III (600-800°C), which shows a large shrinkage to a 'sintering point' and then sometimes expansion. The temperature of the sintering point is affected by many factors, such as the solid materials, the calcium content, and the molar ratio of SiO2/Na2O used in the activator, which effectively defines geopolymer microstructure [42]. For example, the sintering point seems not to appear before 900°C if metakaolin is used as the raw material, and the samples are cured to maturity [31,43].…”

Section: Thermal Resistancementioning

confidence: 99%

Mechanical, thermal insulation, thermal resistance and acoustic absorption properties of geopolymer foam concrete

Zhang

Provis

Reid³

et al. 2015

Cement and Concrete Composites

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463

160

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This study reports the synthesis and characterization of geopolymer foam concrete (GFC). A Class F fly ash with partial slag substitution was used for GFC synthesis by mechanical mixing of preformed foam. The GFCs exhibited 28 day compressive strengths ranging from 3 to 48 MPa with demolded densities from 720 to 1600 kg/m 3 (105°C oven-dried densities from 585 to 1370 kg/m 3 ), with the different densities achieved through alteration of the foam content.The thermal conductivity of GFCs was in the range 0.15 to 0.48 W/m·K, showing better thermal insulation properties than normal Portland cement foam concrete at the same density and/or at the same strength. The GFC derived from alkali activation of fly ash as a sole precursor showed excellent strength retention after heating to temperatures from 100 to 800°C, and the post-cooling compressive strength increased by as much as 100% after exposure at 800°C due to densification and phase transformations. Partial substitution of slag for fly ash increased the strength of GFC at room temperature, but led to notable shrinkage and strength Preprint of: Z Zhang, JL Provis, A Reid, H Wang, Mechanical, thermal insulation, thermal resistance and acoustic absorption properties of geopolymer foam concrete (GFC), Cement and Concrete Composites, 62(2015): 97-105. Final published version is at: http://dx.doi.org/10.1016/j.cemconcomp.2015.03.013 2 loss at high temperature. Thin GFC panels (20 -25 mm) exhibited acoustic absorption coefficients of 0.7-1.0 at 40 to 150 Hz, and 0.1-0.3 at 800 to 1600 Hz.

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Understanding the relationship between geopolymer composition, microstructure and mechanical properties

Cited by 1,479 publications

References 33 publications

Waste glass from end-of-life fluorescent lamps as raw material in geopolymers

Waste glass from end-of-life fluorescent lamps as raw material in geopolymers

A review on alkaline activation: new analytical perspectives

Mechanical, thermal insulation, thermal resistance and acoustic absorption properties of geopolymer foam concrete

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