Comparison of One-Part and Two-Part Alkali-Activated Metakaolin and Blast Furnace Slag
Isabel Pol Segura, Tero Luukkonen, Juho Yliniemi, Harisankar Sreenivasan, Anne Juul Damø, Lars Skaarup Jensen, Mariana Moreira Cavalcanti Canut, Anu M. Kantola, Ville‐Veikko Telkki, Peter Arendt Jensen
Abstract
Abstract One-part alkali-activated materials prepared with solid-form alkali activator are gaining attention in the construction industry, as they are an easier and safer approach for cast-in-situ applications in comparison with two-part approach (i.e., involving the use of alkali-activator solutions). The present study compares the one-part and conventional two-part mixing methods with two aluminosilicate precursors, metakaolin and ground granulated blast-furnace slag, using identical mix designs (in terms of molar ratios of SiO 2 , Al 2 O 3 , and Na 2 O) with both preparation methods. The results revealed that using one-part mix delays the setting time, increases the heat of reaction, decreases the shrinkage, and reaches between 80 and 85% of the compressive strength of the two-part mix. In addition, scanning electron microscopy, thermogravimetric analysis, and X-ray diffraction analysis showed no major differences between one- and two-part. However, energy-dispersive X-ray spectroscopy and magic angle spinning nuclear magnetic resonance experiments indicated that the extent of reaction in two-part alkali-activated mixes is higher than for one-part. Graphical Abstract