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Casting process improvement by optimization of mixture composition and high range water reducing agent modification
- Since its invention in the early 1990’s, self-consolidating concrete has never become well established in the ready-mix sectors worldwide. The reason for this can be mainly found in the fact that the sophisticated compositions are sensitive against changing environments. This lack of robustness can be attributed to the interaction between cement hydration reaction and high range water reducing agent (HRWRA). Understanding the relevant mechanisms that control the initial flow performance as well as the flow retention helps optimizing SCC mixtures that perform either steadily in one specific environment or that perform largely similarly at steadily changing environments. This paper depicts how HRWRAs interact with clinker and hydration phases and discusses the important role of the charge density of a polycarboxylic HRWRA in the way the rheology is affected. Based on rheometric results and observations of the Vicat setting times, it is shown that increasing charge densities of the HRWRASince its invention in the early 1990’s, self-consolidating concrete has never become well established in the ready-mix sectors worldwide. The reason for this can be mainly found in the fact that the sophisticated compositions are sensitive against changing environments. This lack of robustness can be attributed to the interaction between cement hydration reaction and high range water reducing agent (HRWRA). Understanding the relevant mechanisms that control the initial flow performance as well as the flow retention helps optimizing SCC mixtures that perform either steadily in one specific environment or that perform largely similarly at steadily changing environments. This paper depicts how HRWRAs interact with clinker and hydration phases and discusses the important role of the charge density of a polycarboxylic HRWRA in the way the rheology is affected. Based on rheometric results and observations of the Vicat setting times, it is shown that increasing charge densities of the HRWRA and decreasing water to powder ratios (w/p) reduce the flow retention and have lesser retarding effect on the setting. Based on the discussion, optimization procedures for the mixture composition and the HRWRA modification are suggested to achieve optimized performance for varying environmental situations or highest robustness for specific conditions.…
Autor*innen: | Wolfram SchmidtORCiD, H.J.H. Brouwers, Hans-Carsten KühneORCiD, Birgit MengORCiD |
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Persönliche Herausgeber*innen: | K. Wang, S.P. Shah, K. Khayat |
Dokumenttyp: | Beitrag zu einem Tagungsband |
Veröffentlichungsform: | Graue Literatur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | SCC 2013 - 5th North American conference on the design and use of self-consolidating concrete (Proceedings) |
Jahr der Erstveröffentlichung: | 2013 |
Erste Seite: | 1 |
Letzte Seite: | 10 |
Freie Schlagwörter: | Adsorption; Cement hydration; Environmental conditions; Mixture composition; Polycarboxylate |
Veranstaltung: | SCC 2013 - 5th North American conference on the design and use of self-consolidating concrete |
Veranstaltungsort: | Chicago, IL, USA |
Beginndatum der Veranstaltung: | 12.05.2013 |
Enddatum der Veranstaltung: | 15.05.2013 |
Verfügbarkeit des Dokuments: | Datei im Netzwerk der BAM verfügbar ("Closed Access") |
Datum der Freischaltung: | 20.02.2016 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 03.06.2013 |