Activator Anion Influences the Nanostructure of Alkali-Activated Slag Cements
نویسندگان
چکیده
Alkali-activated materials are promising low-carbon alternatives to Portland cement; however, there remains an absence of a fundamental understanding the effect different activator types on their reaction products at atomic scale. Solid-state 27Al and 29Si magic angle spinning (MAS) nuclear magnetic resonance (NMR) spectroscopy 1H–29Si cross-polarization MAS NMR used reveal anion nanostructure, cross-linking, local hydration aged alkali-activated slag cements. The main product identified is mixed cross-linked/non-cross-linked sodium-substituted calcium aluminosilicate hydrate (C–(N)–A–S–H) gel with structure comparable tobermorite 11 Å. Analysis kinetics revealed that higher content soluble silicate in promoted incorporation Al into chains C–(N)–A–S–H gels, charge-balanced preferentially by protons within interlayer. In sodium carbonate-activated cements, gels instead Ca2+ or AlV ions. Hydrotalcite was observed as secondary independent quantities carbonate increases. presence silicates promotes formation Al-rich (N–A–S–H) which not when using activator. These results demonstrate type significant differences nanostructure binding phases forming This explains properties these activators.
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ژورنال
عنوان ژورنال: Journal of Physical Chemistry C
سال: 2021
ISSN: ['1932-7455', '1932-7447']
DOI: https://doi.org/10.1021/acs.jpcc.1c07328