Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Comparison of the Pozzolanic Reactivity for Flash and Soak Calcined Clays in Portland Cement Blends
The increased attention towards the use of calcined clays as supplementary cementitious materials (SCM’s) has prompted several studies of calcined kaolinite (metakaolin) and to a lesser extent also of heat-treated montmorillonite. However, a major part of these studies does not pay specific attention to the calcination process itself. Furthermore, most studies have been performed on phase-pure clays and such clays are not economically viable for applications as SCM’s at an industrial scale. In this work we investigate the reactivity of SCM’s produced by flash calcination of a natural kaolinite sample and a natural mixed smectite/illite sample. Several key properties of the flash calcined materials are tested and compared to calcined clays obtained by a conventional soak-calcination method. The analyses include characterization of physical properties such as BET surface area, specific density and particle fineness and of the microstructure and degree of reaction by powder XRD as well as 29Si and 27Al MAS NMR. Moreover, the pozzolanic reactivity of the SCM’s are investigated by a Chapelle-like test combined with NMR studies of Portland cement—SCM paste samples at different hydration times. Finally, the performance of mortar samples produced with a 35 wt% SCM substitution level is tested with respect to compressive strength and water requirement following the ASTM standard.
Comparison of the Pozzolanic Reactivity for Flash and Soak Calcined Clays in Portland Cement Blends
The increased attention towards the use of calcined clays as supplementary cementitious materials (SCM’s) has prompted several studies of calcined kaolinite (metakaolin) and to a lesser extent also of heat-treated montmorillonite. However, a major part of these studies does not pay specific attention to the calcination process itself. Furthermore, most studies have been performed on phase-pure clays and such clays are not economically viable for applications as SCM’s at an industrial scale. In this work we investigate the reactivity of SCM’s produced by flash calcination of a natural kaolinite sample and a natural mixed smectite/illite sample. Several key properties of the flash calcined materials are tested and compared to calcined clays obtained by a conventional soak-calcination method. The analyses include characterization of physical properties such as BET surface area, specific density and particle fineness and of the microstructure and degree of reaction by powder XRD as well as 29Si and 27Al MAS NMR. Moreover, the pozzolanic reactivity of the SCM’s are investigated by a Chapelle-like test combined with NMR studies of Portland cement—SCM paste samples at different hydration times. Finally, the performance of mortar samples produced with a 35 wt% SCM substitution level is tested with respect to compressive strength and water requirement following the ASTM standard.
Comparison of the Pozzolanic Reactivity for Flash and Soak Calcined Clays in Portland Cement Blends
RILEM Bookseries
Scrivener, Karen (Herausgeber:in) / Favier, Aurélie (Herausgeber:in) / Rasmussen, Kasper E. (Autor:in) / Moesgaard, Mette (Autor:in) / Køhler, Lea L. (Autor:in) / Tran, Thuan T. (Autor:in) / Skibsted, Jørgen (Autor:in)
Calcined Clays for Sustainable Concrete ; Kapitel: 19 ; 151-157
RILEM Bookseries ; 10
08.05.2015
7 pages
Aufsatz/Kapitel (Buch)
Elektronische Ressource
Englisch
Pozzolanic reactivity of pure calcined clays
| Online Contents | 2016
Pozzolanic Properties of Flash-Calcined Kaolinite: A Comparative Study with Soak-Calcined Products
| Online Contents | 1995
Pozzolanic reactivity of pure calcined clays
| Online Contents | 2016
Pozzolanic Properties of Flash-Calcined Kaolinite: A Comparative Study with Soak-Calcined Products
| British Library Online Contents | 1995