Method to Stop Geopolymer Reaction

Xu, Chao; Meawad, Amr; Struble, Leslie J.

doi:10.1111/jace.13071

Cited by 74 publications

(43 citation statements)

References 23 publications

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“…Recycle delay was 2.0 s and 8192 scans were acquired. Before the testing, the specimen at set was dried by the solvent extraction . Microstructure of the mix was also examined using a JEOL JSM‐6060 LV (Peabody, MA) scanning electron microscope (SEM) in secondary electron imaging (SEI) mode.…”

Section: Methodsmentioning

confidence: 99%

“…Compared to these techniques, solid‐state 29 Si NMR provides more detailed nanostructural information in terms of atomic connectivity for both zeolites and mature geopolymers. However, this experiment is too slow for probing early‐age reactions in geopolymers . Nanostructural evolution has been investigated in dilute solutions with liquid‐state 29 Si NMR, but not for geopolymer systems in which species are highly concentrated.…”

Section: Introductionmentioning

confidence: 99%

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Setting and nanostructural evolution of metakaolin geopolymer

et al. 2017

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The nanostructural evolution during formation of geopolymers and its correlation with setting have not been well understood. In this study, penetration resistance and ultrasonic wave reflection tests were conducted to measure setting, and solid‐state 27Al NMR and liquid‐state 29Si NMR were used to examine nanostructural changes in a metakaolin geopolymer as a function of time. Aluminum was released rapidly during the first 10 hour after mixing and immediately condensed with silicate species in solution to form larger sized aluminosilicate oligomers, which then condensed to form large structural units. Our evidence suggests these units form near metakaolin particle surface. Smaller sized silicate ions in the sol phase then attach to these units to form a gel with a more interconnected network structure. The initial stage of this attaching process was seen to be associated with set, which in this mixture occurred at 15 hour.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Setting and nanostructural evolution of metakaolin geopolymer

et al. 2017

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“…The polished sample surfaces were coated using a gold sputter coater to eliminate effects of charging during micrograph collection. SEM samples were tested in a state where the alkali activation process has been stopped using the combined water and solvent extraction protocol developed by Chen et al [38]. In summary, it involved stirring the AAB specimen in deionized water and then removing the liquid by centrifuging.…”

Section: Testing Methods and Conditionsmentioning

confidence: 99%

Effects of waste glass on alkali-activated tungsten mining waste: composition and mechanical properties

Kastiukas

Zhou

2017

Mater Struct

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Increasingly more research is being directed towards the valorisation of waste materials as precursors for synthesising alkali-activated binders (AABs). For this study, varying blends of tungsten mining waste (TMW) and waste glass (WG) are activated using a combined sodium hydroxide (SH) and sodium silicate (SS) alkali solution. The activating solution itself is also varied with respect to the quantities of SS and SH to determine their effect on reactant formation and mechanical strength of TMWbased AABs. The results show that an increased WG content can effectively provide an additional source of reactive silica, contribute to the formation of (C, N)-A-S-H gel products and thus significantly improve the mechanical strength. High strength TMW-WG AABs were attributed to a faster TMW dissolution rate and dense microstructure. Such structures were characteristic of formulations with low alkali modulus (SiO 2 / Na 2 O \ 2) combined with a SS/SH weight ratio of 2.8. For the latter, not only was a characteristic slower strength development with increasing alkali content observed, but there was also a limit of alkali metal concentration (Na 2 O * 3.1%) beyond which the strength deteriorated. Furthermore, SEM micrographs disclose that unreacted particles of WG reinforced the matrix by acting as a filler.

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“…When was necessary, as an experimental technique for stopping the process of hydration of the CG, reached the curing age stipulated, acetone and alcohol baths were used in a ratio of 1 for a period of three days with daily replacement of solution [18].…”

Section: Methodology Sample Preparationmentioning

confidence: 99%

Effect of Curing Temperature in the Alkali-Activated Blast-Furnace Slag Paste and Their Structural Influence of Porosity

Medina-Serna¹,

Arredondo-Rea²,

Gómez-Soberón³

et al. 2016

Adv. Sci. Technol. Res. J.

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Due to the environmental problem posed by the use of Portland cement as construction material, it becomes necessary the search for supplementary cementitious materials that mitigate the ecological damage caused by it. Because the chemical similarity and the high cementitious powers of the blast furnace slag, it is used in the generation of geopolymers in a cement total replacement. This research focused on the study of the influence of the curing conditions on the final properties of blast furnace slag establishing three variables: no cured process (N-C), cured of controlled temperature of 45°C (CT45-C) and room temperature cure (RT-C); evaluating the mechanical behavior until 28 days of age and the water porosity index. The results show that geopolymers based on blast furnace slag has a behavior similar to hydration maturity of Portland cement and curing process decreases the porosity; On the other hand, applying a controlled temperature generates densest resistant pastes such as the variable CT45-C which reach the highest value of resistance in all curing ages.

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Method to Stop Geopolymer Reaction

Cited by 74 publications

References 23 publications

Setting and nanostructural evolution of metakaolin geopolymer

Setting and nanostructural evolution of metakaolin geopolymer

Effects of waste glass on alkali-activated tungsten mining waste: composition and mechanical properties

Effect of Curing Temperature in the Alkali-Activated Blast-Furnace Slag Paste and Their Structural Influence of Porosity

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