Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties
This study investigates the relationships between the hydration kinetics of waterglass-activated slag and the development of its physical-mechanical properties, as well as its color change. To modify the calorimetric response of alkali-activated slag, hexylene glycol was selected from various alcoho...
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2023-02-01
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| Online Access: | https://www.mdpi.com/1996-1944/16/5/1908 |
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| author | Vlastimil Bílek Lukáš Kalina Richard Dvořák Radoslav Novotný Jiří Švec Jiří Másilko František Šoukal |
| author_facet | Vlastimil Bílek Lukáš Kalina Richard Dvořák Radoslav Novotný Jiří Švec Jiří Másilko František Šoukal |
| author_sort | Vlastimil Bílek |
| collection | DOAJ |
| description | This study investigates the relationships between the hydration kinetics of waterglass-activated slag and the development of its physical-mechanical properties, as well as its color change. To modify the calorimetric response of alkali-activated slag, hexylene glycol was selected from various alcohols for in-depth experiments. In presence of hexylene glycol, the formation of initial reaction products was restricted to the slag surface, which drastically slowed down the further consumption of dissolved species and slag dissolution and consequently delayed the bulk hydration of the waterglass-activated slag by several days. This allowed to show that the corresponding calorimetric peak is directly related to the rapid evolution of the microstructure and physical-mechanical parameters and to the onset of a blue/green color change recorded as a time-lapse video. Workability loss was correlated with the first half of the second calorimetric peak, while the most rapid increase in strengths and autogenous shrinkage was related to the third calorimetric peak. Ultrasonic pulse velocity increased considerably during both the second and third calorimetric peak. Despite the modified morphology of the initial reaction products, the prolonged induction period, and the slightly reduced degree of hydration induced by hexylene glycol, the overall mechanism of alkaline activation remained unchanged in the long-term perspective. It was hypothesized that the main issue of the use of organic admixtures in alkali-activated systems is the destabilizing effect of these admixtures on soluble silicates introduced into the system with an activator. |
| first_indexed | 2024-03-11T07:19:41Z |
| format | Article |
| id | doaj.art-81b51f795221468aa8066221be7472c3 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-11T07:19:41Z |
| publishDate | 2023-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-81b51f795221468aa8066221be7472c32023-11-17T08:04:33ZengMDPI AGMaterials1996-19442023-02-01165190810.3390/ma16051908Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its PropertiesVlastimil Bílek0Lukáš Kalina1Richard Dvořák2Radoslav Novotný3Jiří Švec4Jiří Másilko5František Šoukal6Institute of Materials Science, Faculty of Chemistry, Brno University of Technology, 612 00 Brno, Czech RepublicInstitute of Materials Science, Faculty of Chemistry, Brno University of Technology, 612 00 Brno, Czech RepublicInstitute of Physics, Faculty of Civil Engineering, Brno University of Technology, 612 00 Brno, Czech RepublicInstitute of Materials Science, Faculty of Chemistry, Brno University of Technology, 612 00 Brno, Czech RepublicInstitute of Materials Science, Faculty of Chemistry, Brno University of Technology, 612 00 Brno, Czech RepublicInstitute of Materials Science, Faculty of Chemistry, Brno University of Technology, 612 00 Brno, Czech RepublicInstitute of Materials Science, Faculty of Chemistry, Brno University of Technology, 612 00 Brno, Czech RepublicThis study investigates the relationships between the hydration kinetics of waterglass-activated slag and the development of its physical-mechanical properties, as well as its color change. To modify the calorimetric response of alkali-activated slag, hexylene glycol was selected from various alcohols for in-depth experiments. In presence of hexylene glycol, the formation of initial reaction products was restricted to the slag surface, which drastically slowed down the further consumption of dissolved species and slag dissolution and consequently delayed the bulk hydration of the waterglass-activated slag by several days. This allowed to show that the corresponding calorimetric peak is directly related to the rapid evolution of the microstructure and physical-mechanical parameters and to the onset of a blue/green color change recorded as a time-lapse video. Workability loss was correlated with the first half of the second calorimetric peak, while the most rapid increase in strengths and autogenous shrinkage was related to the third calorimetric peak. Ultrasonic pulse velocity increased considerably during both the second and third calorimetric peak. Despite the modified morphology of the initial reaction products, the prolonged induction period, and the slightly reduced degree of hydration induced by hexylene glycol, the overall mechanism of alkaline activation remained unchanged in the long-term perspective. It was hypothesized that the main issue of the use of organic admixtures in alkali-activated systems is the destabilizing effect of these admixtures on soluble silicates introduced into the system with an activator.https://www.mdpi.com/1996-1944/16/5/1908alkali-activated slagcalorimetrymicrostructureretardationpore solutionorganic admixture |
| spellingShingle | Vlastimil Bílek Lukáš Kalina Richard Dvořák Radoslav Novotný Jiří Švec Jiří Másilko František Šoukal Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties Materials alkali-activated slag calorimetry microstructure retardation pore solution organic admixture |
| title | Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties |
| title_full | Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties |
| title_fullStr | Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties |
| title_full_unstemmed | Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties |
| title_short | Correlating Hydration of Alkali-Activated Slag Modified by Organic Additives to the Evolution of Its Properties |
| title_sort | correlating hydration of alkali activated slag modified by organic additives to the evolution of its properties |
| topic | alkali-activated slag calorimetry microstructure retardation pore solution organic admixture |
| url | https://www.mdpi.com/1996-1944/16/5/1908 |
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