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Mode of operation of polysaccharide stabilising agent in cement based systems and interactions with superplasticisers

  • Polysaccharides are incorporated into cement based systems in order to modify the rheological properties. Typically cellulose ethers, sphingan gums or starch ethers are applied. Depending upon their chemistry, molecular architecture, and adsorption tendency, polysaccharides interact differently with the entire cementitious system. Some stabilising agents like diutan gum mainly affect the cementitious paste; other stabilising agents like starch tend to interact with the sand fraction and even with the coarse aggregates. Cellulose shows more divers performances. Often stabilising admixtures like polysaccharides are used, when sophisticated rheological properties are adjusted. Therefore, polysaccharides are often used in combination with superplasticisers. This can cause interactions, particularly when the stabilising agent shows a strong tendency to adsorb on particle surfaces. Adsorptive stabilising agents may reduce the amount of adsorbed superplasticisers, thus affecting bothPolysaccharides are incorporated into cement based systems in order to modify the rheological properties. Typically cellulose ethers, sphingan gums or starch ethers are applied. Depending upon their chemistry, molecular architecture, and adsorption tendency, polysaccharides interact differently with the entire cementitious system. Some stabilising agents like diutan gum mainly affect the cementitious paste; other stabilising agents like starch tend to interact with the sand fraction and even with the coarse aggregates. Cellulose shows more divers performances. Often stabilising admixtures like polysaccharides are used, when sophisticated rheological properties are adjusted. Therefore, polysaccharides are often used in combination with superplasticisers. This can cause interactions, particularly when the stabilising agent shows a strong tendency to adsorb on particle surfaces. Adsorptive stabilising agents may reduce the amount of adsorbed superplasticisers, thus affecting both viscosity and yield stress, while non-adsorptive stabilising agents mainly affect the plastic viscosity independently of the superplasticiser. Due to the strong influence of superplasticisers on the yield stress, influences of the stabilising agent on the yield stress retreat into the background, so that their major effect is an increase of the viscosity. The paper provides a comprehensive overview of how different polysaccharide superplasticisers affect cementitious flowable systems and points out the challenges of the combined use of polysaccharides and superplasticisers. Based on rheometric experiments and Observations of the hydration process, time dependent effects on the workability as well as of the hydration of cement are presented.zeige mehrzeige weniger

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Metadaten
Autor*innen:Wolfram SchmidtORCiD
Persönliche Herausgeber*innen:Sofiane Amziane, M. Sonebi, K. Charlet
Dokumenttyp:Beitrag zu einem Tagungsband
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):ICBBM 2015 - 1st International conference on bio-based building materials (Proceedings)
Jahr der Erstveröffentlichung:2015
Ausgabe/Heft:PRO 99
Erste Seite:100
Letzte Seite:106
Freie Schlagwörter:Chloride migration; Corrosion potential; Electrical resistivity; Freeze-thaw; Water absorption
Veranstaltung:ICBBM 2015 - 1st International conference on bio-based building materials
Veranstaltungsort:Clermont-Ferrand, France
Beginndatum der Veranstaltung:22.06.2015
Enddatum der Veranstaltung:24.06.2015
ISBN:978-2-35158-154-4
Bemerkung:
Serientitel: Rilem proceedings – Series title: Rilem proceedings
Verfügbarkeit des Dokuments:Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")
Datum der Freischaltung:20.02.2016
Referierte Publikation:Nein
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