Novel perspective to explain the retarding effect of organic admixtures in silicate-activated slag

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26310%2F22%3APU145959" target="_blank" >RIV/00216305:26310/22:PU145959 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Novel perspective to explain the retarding effect of organic admixtures in silicate-activated slag

Popis výsledku v původním jazyce

One with the issues of alkali-activated materials is their incompatibility with conventional organic admixtures, which means that they do not improve their properties as expected on the basis of their role in the Portland cement-based system or even have adverse effects. This is also true for hexylene glycol, on which the commercial shrinkage-reducing admixture is based. In previous studies, we observed that it can reduce the drying shrinkage of alkali-activated slag (AAS), but the main reason was its adverse effect on the hydration of AAS since the early ages and related coarse pore structure. In the present study, calorimetric studies showed that a great effect of hexylene glycol and some other alcohols is especially pronounced for a high silicate modulus (around two). This was confirmed by gelation experiments, in which the activating solution was mixed with calcium hydroxide, and organic additives were used. These tests revealed that the acceleration of gelation of silicates occurs for the same admixtures as the retardation of hydration and follows the same trend. A similar effect was observed for the gelation of silicate sol by NaCl solution, showing that the destabilization of silicates by organic additives is at the origin of the affected hydration of silicate-activated slag.

Název v anglickém jazyce

Novel perspective to explain the retarding effect of organic admixtures in silicate-activated slag

Popis výsledku anglicky

One with the issues of alkali-activated materials is their incompatibility with conventional organic admixtures, which means that they do not improve their properties as expected on the basis of their role in the Portland cement-based system or even have adverse effects. This is also true for hexylene glycol, on which the commercial shrinkage-reducing admixture is based. In previous studies, we observed that it can reduce the drying shrinkage of alkali-activated slag (AAS), but the main reason was its adverse effect on the hydration of AAS since the early ages and related coarse pore structure. In the present study, calorimetric studies showed that a great effect of hexylene glycol and some other alcohols is especially pronounced for a high silicate modulus (around two). This was confirmed by gelation experiments, in which the activating solution was mixed with calcium hydroxide, and organic additives were used. These tests revealed that the acceleration of gelation of silicates occurs for the same admixtures as the retardation of hydration and follows the same trend. A similar effect was observed for the gelation of silicate sol by NaCl solution, showing that the destabilization of silicates by organic additives is at the origin of the affected hydration of silicate-activated slag.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20101 - Civil engineering

Projekt

<a href="/cs/project/GA20-26896S" target="_blank" >GA20-26896S: Cesta k vývoji organických přísad pro systémy na bázi alkalicky aktivované strusky</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

SP-354: Superplasticizers and Other Chemical Admixtures in Concrete - Conference Proceedings

ISBN

978-1-64195-185-2

ISSN

0193-2527

e-ISSN

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Počet stran výsledku

11

Strana od-do

49-60

Název nakladatele

American Concrete Institute

Místo vydání

Milán

Místo konání akce

Milán

Datum konání akce

10. 7. 2022

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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