Calorimetry Study of the Influence of Portland Cement Content, Slag/Fly Ash Ratio, and Activator Type on the Early Hydration of Hybrid Cements
- Hybrid cements (cements composed of Portland clinker, supplementary cementitious materials and an alkaline activator) potentially combine advantages of conventional cements with those of alternative binders, such as low heat of hydration and improved durability in some environments. While fly ash-based hybrid cements have been studied in considerable detail, slag-dominated hybrid cements appear to have received less attention. Here, the latter materials have been studied by isothermal calorimetry, X-ray diffraction and strength testing. The heat of hydration of these cements was as low as ~50% of that of an ordinary Portland cement, while their strength after 28-day curing was in the range 31–61 MPa. The phase assemblages after 28-day curing depended on the activator, with Na2SO4 leading to ettringite and Na2CO3 leading to hemicarbonate formation, respectively, besides C–A–S–H, portlandite and hydrotalcite. The U phase was identified when a high Na2SO4 dose and/or fly ash was employed.Hybrid cements (cements composed of Portland clinker, supplementary cementitious materials and an alkaline activator) potentially combine advantages of conventional cements with those of alternative binders, such as low heat of hydration and improved durability in some environments. While fly ash-based hybrid cements have been studied in considerable detail, slag-dominated hybrid cements appear to have received less attention. Here, the latter materials have been studied by isothermal calorimetry, X-ray diffraction and strength testing. The heat of hydration of these cements was as low as ~50% of that of an ordinary Portland cement, while their strength after 28-day curing was in the range 31–61 MPa. The phase assemblages after 28-day curing depended on the activator, with Na2SO4 leading to ettringite and Na2CO3 leading to hemicarbonate formation, respectively, besides C–A–S–H, portlandite and hydrotalcite. The U phase was identified when a high Na2SO4 dose and/or fly ash was employed. Na2SO4 accelerated the early reaction of the Portland clinker, while Na2CO3 appeared to decrease the extent of reaction of the clinker and led to a shift of the second hydration peak (likely related to slag reaction) to later hydration times, as did substitution of slag by fly ash. Increasing Na2SO4 dose from 4 to 6% did not lead to further acceleration of hydration or improved strength.…
Autor*innen: | Gregor GluthORCiD, S. Garel |
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Persönliche Herausgeber*innen: | I. B. Valente, A. Ventura Gouveia, S. S. Dias |
Dokumenttyp: | Beitrag zu einem Tagungsband |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Proceedings of the 3rd RILEM Spring Convention and Conference (RSCC 2020) – Volume 2: New Materials and Structures for Ultra-durability |
Jahr der Erstveröffentlichung: | 2021 |
Organisationseinheit der BAM: | 7 Bauwerkssicherheit |
7 Bauwerkssicherheit / 7.4 Baustofftechnologie | |
Verlag: | Springer |
Verlagsort: | Cham |
Erste Seite: | 217 |
Letzte Seite: | 226 |
DDC-Klassifikation: | Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Angewandte Physik |
Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurbau | |
Freie Schlagwörter: | Alkali-activated materials; Calorimetry; Early hydration; Hybrid cements |
Themenfelder/Aktivitätsfelder der BAM: | Energie |
Energie / Kerntechnische Entsorgung | |
Infrastruktur | |
Veranstaltung: | 3rd RILEM Spring Convention and Conference (RSCC 2020) |
Veranstaltungsort: | Guimarães, Portugal |
Beginndatum der Veranstaltung: | 10.03.2020 |
Enddatum der Veranstaltung: | 14.03.2020 |
DOI: | 10.1007/978-3-030-76551-4_20 |
ISBN: | 978-3-030-76550-7 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 09.08.2021 |
Referierte Publikation: | Nein |