The effect of temperature on the geopolymerization process of a metakaolin-based geopolymer

Muñiz-Villarreal, M.S.; Manzano-Ramı́rez, A.; Sampieri-Bulbarela, S.; Gasca-Tirado, José Ramón; Reyes-Araiza, José Luis; Rubio-Ávalos, J.C.; Pérez-Bueno, J.J.; Apátiga, L.M.; Zaldívar-Cadena, A.A.; Amigó, V.

doi:10.1016/j.matlet.2010.12.049

Cited by 193 publications

(76 citation statements)

References 14 publications

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“…For a given curing temperature and activating alkali, porosity and compressive strength show an inverse proportion, as reported in the literature (21,26,56). This relationship reflects compositional differences in the geopolymers, with a similar pattern regardless of the alkali and the curing temperature.…”

Section: Discussionsupporting

confidence: 82%

Contributions to the study of porosity in fly ash-based geopolymers. Relationship between degree of reaction, porosity and compressive strength

2016

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ABSTRACT:The main contribution of this paper relates to the development of a systematic study involving a set of parameters which could potentially have an impact on geopolymer properties: curing temperature, type of activating solution, alkali metal in solution, incorporation of slag (Ca source) and type of slag used. The microstructures, degrees of reaction, porosities and compressive strengths of geopolymers have been evaluated. Geopolymers prepared with soluble silicate presented a more compacted and closed structure, a larger amount of gel, lower porosity and greater compressive strength than those prepared with hydroxides. On the other hand, Na-geopolymers were more porous but more resistant than K-geopolymers. Although there is an inverse relation between degree of reaction and porosity, between compressive strength and porosity it is not always inversely proportional and could, in some cases, be masked by changes produced in other influencing parameters. RESUMEN: Contribuciones al estudio de la porosidad de geopolímeros basados en cenizas volantes. Relación entre grado de reacción, porosidad y resistencia a compresión.La principal contribución de este documento es el desarrollo de un estudio sistemático implicando una serie de parámetros que podrían afectar a las propiedades de los geopolímeros: temperatura de curado, solución activadora, metal alcalino de la solución, incorporación de escorias (fuente de calcio) y tipo de escorias. Se han evaluado: microestructura, grado de reacción, porosidad y resistencia a compresión. Los geopolímeros preparados con silicatos presentaron un microestructura más densa y compacta, una mayor cantidad del gel geopolimérico, menor porosidad y mejores propiedades mecánicas que los preparados con hidróxidos. Los geopolímeros preparados con sales de sodio fueron más porosos pero más resistentes que los preparados con sales potasio. Aunque existe una relación inversa entre el grado de reacción y la porosidad, en algunos casos, la relación entre resistencia y porosidad es inexistente ya que puede estar enmascarada por cambios producidos por otros parámetros que afecten a la reacción.

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Section: Discussionsupporting

confidence: 82%

Contributions to the study of porosity in fly ash-based geopolymers. Relationship between degree of reaction, porosity and compressive strength

2016

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“…e mold is removed after hardening of the specimens. At the end of the curing regime, after 28 days, the samples were dried well at 60°C for 24 h in order to complete the geopolymerization [19] and then exposed to compressive strength measurements. Fresh geopolymer foams were then placed in an oven at 70°C to constant weight.…”

Section: Sample Preparationsmentioning

confidence: 99%

Physicochemical Characterization of Geopolymer Binders and Foams Made from Tunisian Clay

Messaoud

Hamdi

Srasra³

2018

Advances in Materials Science and Engineering

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Illito-kaolinitic clay rich in hematite from south Tunisia was investigated in view of producing geopolymer materials. Geopolymers with two different densities were elaborated: cement and foam. e effects of activator concentrations on compressive strength, water absorption (durability), open porosity, and bulk density of geopolymers cement were examined, in order to assure optimal geopolymerization conditions. Geopolymer cements aged 28 days with optimum performances were achieved for 13 M of alkaline solution concentration. At these conditions, the compressive strength of prepared geopolymer reaches 27.8 MPa. e addition of silica fume to reactant geopolymer mixture induces modification of geopolymer density and decrease in the compressive strength of the final product. Geopolymer materials based on calcined Tunisian clay can be suggested as sustainable and cost-effective cement that may be applied to alternate Portland cement in many construction applications.

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“…Many parameters affect the heat evolution of OPC binder concretes, including fly ash replacement, superplasticiser dosage (Atiş, 2002) characteristics of the cement, initial material temperature, volume of poured concrete (Tarasov et al, 2010), which leads to the question of what happens to alkali-activated fly ash when it is exposed to medium-high temperatures. Numerous works on heat release measurements of different alkali-activated systems have been conducted (Alonso and Palomo, 2001b;Brough and Atkinson, 2002;Chithiraputhiran and Neithalath, 2013;Fernández-Jiménez and Puertas, 1997;Muñiz-Villareal et al, 2011;Palomo et al, 1999;Zhang et al, 2012). Zhang et al (2013) reported that the heat release rate of metakaolin geopolymers increased monotonically with increasing sodium hydroxide concentration.…”

Section: Introductionmentioning

confidence: 99%

Temperature rise and initial shrinkage of alkali-activated fly ash cement pastes

Shekhovtsova

Kovtun

Kearsley

2016

Advances in Cement Research

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This paper reports on core temperature development and initial shrinkage of fly ash cement pastes activated with sodium hydroxide solution at different concentrations during elevated-temperature curing at 60°C. The results indicate that a high sodium hydroxide concentration might result in a substantial rise in the core temperature of samples, dependent on the mould size and ratio of paste to oven volume. An increase in alkali concentration was also found to increase the initial shrinkage of the pastes during elevated-temperature curing. Excessive initial shrinkage and temperature increase might lead to the appearance of internal stresses in the pastes, which can affect the material performance. mass of mould with sample after elevatedtemperature curing (g) m m mass of empty mould (g) T p peak temperature (°C) t p time of appearance of peak temperature after the start of elevated-temperature curing (min) Notation

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The effect of temperature on the geopolymerization process of a metakaolin-based geopolymer

Cited by 193 publications

References 14 publications

Contributions to the study of porosity in fly ash-based geopolymers. Relationship between degree of reaction, porosity and compressive strength

Contributions to the study of porosity in fly ash-based geopolymers. Relationship between degree of reaction, porosity and compressive strength

Physicochemical Characterization of Geopolymer Binders and Foams Made from Tunisian Clay

Temperature rise and initial shrinkage of alkali-activated fly ash cement pastes

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