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Formation of Geopolymers Using Sodium Silicate Solution and Aluminum Orthophosphate
- This paper reports the formation and structure of fast setting geopolymers activated by using three sodium silicate solutions with different modules (1.6, 2.0 and 2.4) and a berlinite-type aluminum orthophosphate. By varying the concentration of the aluminum orthophosphate, different Si/Al-ratios were established (6, 3 and 2). Reaction kinetics of binders were determined by isothermal calorimetricThis paper reports the formation and structure of fast setting geopolymers activated by using three sodium silicate solutions with different modules (1.6, 2.0 and 2.4) and a berlinite-type aluminum orthophosphate. By varying the concentration of the aluminum orthophosphate, different Si/Al-ratios were established (6, 3 and 2). Reaction kinetics of binders were determined by isothermal calorimetric measurements at 20 °C. X-ray diffraction analysis as well as nuclear magnetic resonance (NMR) measurements were performed on binders to determine differences in structure by varying the alkalinity of the sodium silicate solutions and the Si/Al-ratio. The calorimetric results indicated that the higher the alkalinity of the sodium silicate solution, the higher the solubility and degree of conversion of the aluminum orthophosphate. The results of X-ray diffraction and Rietveldt analysis, as well as the NMR measurements, confirmed the assumption of the calorimetric experiments that first the aluminum orthophosphate was dissolved and then a polycondensation to an amorphous aluminosilicate network occurred. The different amounts of amorphous phases formed as a function of the alkalinity of the sodium silicate solution, indicate that tetrahydroxoaluminate species were formed during the dissolution of the aluminum orthophosphate, which reduce the pH value. This led to no further dissolution of the aluminum orthophosphate, which remained unreacted.…
Dokumentart: | Artikel (Wissenschaftlicher) |
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Verfasserangaben: | Dipl.-Ing. Stephan PartschefeldGND, Dr. rer. nat. Torben WiegandORCiDGND, Dr.-Ing. Frank BellmannORCiD, Prof. Dr.-Ing. Dipl.-Chem. Andrea OsburgORCiDGND |
DOI (Zitierlink): | https://doi.org/10.3390/ma13184202Zitierlink |
URN (Zitierlink): | https://nbn-resolving.org/urn:nbn:de:gbv:wim2-20210122-43378Zitierlink |
URL: | https://www.mdpi.com/1996-1944/13/18/4202 |
Titel des übergeordneten Werkes (Englisch): | Materials |
Verlag: | MDPI |
Verlagsort: | Basel |
Sprache: | Englisch |
Datum der Veröffentlichung (online): | 20.01.2021 |
Datum der Erstveröffentlichung: | 21.09.2020 |
Datum der Freischaltung: | 22.01.2021 |
Veröffentlichende Institution: | Bauhaus-Universität Weimar |
Institute und Partnereinrichtugen: | Fakultät Bauingenieurwesen / Professur Bauchemie und Polymere Werkstoffe |
Jahrgang: | 2020 |
Ausgabe / Heft: | Volume 13, issue 18, article 4202 |
Seitenzahl: | 16 |
Erste Seite: | 1 |
Letzte Seite: | 16 |
Freies Schlagwort / Tag: | OA-Publikationsfonds2020 alumosilicate; berlinite; geopolymer; sodium silicate solution |
GND-Schlagwort: | Geopolymere |
DDC-Klassifikation: | 600 Technik, Medizin, angewandte Wissenschaften / 660 Chemische Verfahrenstechnik / 668 Technik anderer organischer Produkte |
BKL-Klassifikation: | 51 Werkstoffkunde / 51.60 Keramische Werkstoffe, Hartstoffe |
Open Access Publikationsfonds: | Open-Access-Publikationsfonds 2020 |
Lizenz (Deutsch): | Creative Commons 4.0 - Namensnennung (CC BY 4.0) |