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Experimental Study of Slag Changes during the Very Early Stages of Its Alkaline Activation
| Content Provider | MDPI |
|---|---|
| Author | Vlastimil, Bílek Petr, Hrubý Jan, Koplík Jakub, Kříkala Iliushchenko, Valeriia Marko, Michal Hajzler, Jan Kalina, Lukáš |
| Copyright Year | 2021 |
| Description | The very early stages of alkaline activation of slag control its rheology and setting, but also affect its hydration, which occurs later. Simultaneously, these parameters are dictated by the nature and dose of the alkaline activator. Therefore, we investigated and compared the changes in slag particles (SEM, BET, laser diffraction), as well as in the pore solution composition (ICP–OES), pH, and conductivity, of alkali-activated slag (AAS) pastes containing the three most common sodium activators (waterglass, hydroxide, and carbonate) and water during the first 24 h of its activation. To ensure the best possible comparability of the pastes, a fairly nontraditional mixture design was adopted, based on the same concentration of $Na^{+}$ (4 $mol/dm^{3}$) and the same volume fraction of slag in the paste (0.50). The results were correlated with the pastes’ hydration kinetics (isothermal calorimetry), structural build-up (oscillatory rheology), and setting times (Vicat). Great differences were observed in most of these properties, in the formation of hydration products, and in the composition of the pore solution for each activator. The results emphasize the role of the anionic groups in the activators and of the pH, which help predict the sample’s behavior based on its calorimetric curve, and offer data for further comparisons and for the modelling of AAS hydration for specific activators. |
| Starting Page | 231 |
| e-ISSN | 19961944 |
| DOI | 10.3390/ma15010231 |
| Journal | Materials |
| Issue Number | 1 |
| Volume Number | 15 |
| Language | English |
| Publisher | MDPI |
| Publisher Date | 2021-12-29 |
| Access Restriction | Open |
| Subject Keyword | Materials Environmental Engineering Alkali-activated Slag Activator Hydration Kinetics Pore Solution Scanning Electron Microscopy Bet Surface Morphology Hydration Products Setting |
| Content Type | Text |
| Resource Type | Article |
