The Effect of Low Charge Polycarboxylate on C3A Passivation Monitored by Optical Spectroscopy

  • Tricalcium aluminate (C3A) is less than 10 wt.% of the total cement composition; however, during hydration, the soluble C3A plays an important role in cement setting when mixed with the appropriate amount of sulfate.1 A good understanding about the balance of these components is therefore crucial to follow with the rapid growth of substitution materials and the rising levels of aluminate clinker. The aim of this investigation is the use of optical spectroscopy and in-situ X-ray diffraction utilizing a water-soluble organic dye (dye-S) to monitor early hydration of calcium aluminate (C3A) in the presence of 26 wt.% CaS04.2H2O (G) and PCE polymers with different charge densities (PCE-LC and PCE-HC). Phase characterization and optical evaluation were performed using in-situ X-ray diffraction and steady-state fluorescence and diffuse reflectance spectroscopy. Fluorescence spectroscopy of the reference C3A + dye-S revealed a fast decay in fluorescence intensity. However, in the presence ofTricalcium aluminate (C3A) is less than 10 wt.% of the total cement composition; however, during hydration, the soluble C3A plays an important role in cement setting when mixed with the appropriate amount of sulfate.1 A good understanding about the balance of these components is therefore crucial to follow with the rapid growth of substitution materials and the rising levels of aluminate clinker. The aim of this investigation is the use of optical spectroscopy and in-situ X-ray diffraction utilizing a water-soluble organic dye (dye-S) to monitor early hydration of calcium aluminate (C3A) in the presence of 26 wt.% CaS04.2H2O (G) and PCE polymers with different charge densities (PCE-LC and PCE-HC). Phase characterization and optical evaluation were performed using in-situ X-ray diffraction and steady-state fluorescence and diffuse reflectance spectroscopy. Fluorescence spectroscopy of the reference C3A + dye-S revealed a fast decay in fluorescence intensity. However, in the presence of 26 wt.% G (C3A + dye-S + 26 wt.% G), a gradual increase in fluorescence intensity was observed in the first hours of reaction followed by a plateau that subsequently dropped in intensity after eight hours. The addition of PCE-LC and PCE HC to the mixture exhibited changes in the intensity threshold and overall a higher fluorescence intensity. Dye changes during hydration and structural changes will be further discussed.zeige mehrzeige weniger

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Metadaten
Autor*innen:Alejandra Ramirez Caro
Koautor*innen:Jutta Pauli, Berta Mota, Claudia Crasselt, Wolfram Schmidt, Ute Resch-Genger
Dokumenttyp:Posterpräsentation
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2019
Organisationseinheit der BAM:1 Analytische Chemie; Referenzmaterialien
1 Analytische Chemie; Referenzmaterialien / 1.2 Biophotonik
7 Bauwerkssicherheit
7 Bauwerkssicherheit / 7.4 Baustofftechnologie
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:C3A; Dye; Gypsum; Optical Spectroscopy
Themenfelder/Aktivitätsfelder der BAM:Umwelt
Umwelt / Sensorik
Veranstaltung:3rd International Conference on Polycarboxylate Superplasticizers (PCE 2019)
Veranstaltungsort:Munich, Germany
Beginndatum der Veranstaltung:23.10.2019
Enddatum der Veranstaltung:25.10.2019
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:28.10.2019
Referierte Publikation:Nein
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