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The Role of Water Content and Binder to Aggregate Ratio on the Performance of Metakaolin-Based Geopolymer Mortars

Dathe, Felix 1; Overmann, Steffen; Koenig, Andreas; Dehn, Frank 1
1 Institut für Massivbau und Baustofftechnik (IMB), Karlsruher Institut für Technologie (KIT)

Abstract:

Geopolymers are in many applications a perfect alternative to standard cements, especially regarding the sustainable development of green building materials. This experimental study therefore deals with the investigation of different factors, such as the water content and the binder to aggregate ratio, and their influence on the workability of fresh mortar and its mechanical properties and porosity on different size scales. Although increasing the water content improved the workability and flow behaviour of the fresh mortar, at the same time, a reduction in compressive strength in particular and a lesser reduction in flexural strength could be demonstrated. This finding can be attributed to an increase in capillary porosity, as demonstrated by capillary water uptake and mercury intrusion porosimetry measurements. At the same time, the increasing water content led to an improved deaeration effect (low air void content) and to initial segregation (see the µXCT measurements). An alternative approach to enhance the compressive and flexural strengths of the mortar specimens is optimization of the binder to aggregate ratio from 1 to 0.25. This study paves the way for a comprehensive understanding of the underlying chemistry of the geopolymerization reaction and is crucial for the development of sustainable alternatives to cementitious systems.


Verlagsausgabe §
DOI: 10.5445/IR/1000174939
Veröffentlicht am 10.10.2024
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Massivbau und Baustofftechnik (IMB)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2024
Sprache Englisch
Identifikator ISSN: 2075-163X
KITopen-ID: 1000174939
Erschienen in Minerals
Verlag MDPI
Band 14
Heft 8
Seiten Art.-Nr.: 823
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 14.08.2024
Schlagwörter geopolymers; CO2 reduction; common clays; capillary porosity; geopolymerization; alkali activation; metakaolin
Nachgewiesen in Scopus
Web of Science
Dimensions
Globale Ziele für nachhaltige Entwicklung Ziel 7 – Bezahlbare und saubere EnergieZiel 12 – Nachhaltiger Konsum und Produktion
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