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Especies moleculares de silicato y aluminato en cemento anhidro e hidratado
Aditya Rawal1, Benjamin J Smith, George L Athens
1Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
Journal of the American Chemical Society
|May 12, 2010
Resumen
La espectroscopia avanzada de resonancia magnética nuclear (RMN) de estado sólido revela estructuras moleculares distintas en los cementos anhidros e hidratados. Esta técnica diferencia las especies de silicato y aluminato, proporcionando información sobre los procesos de hidratación y fijación del cemento.
Área de la Ciencia:
- Ciencia de los materiales Ciencia de los materiales.
- Química Química es la química.
- La espectroscopia es una técnica de espectroscopia.
Sus antecedentes:
- Comprender la composición del cemento y la estructura molecular es crucial para controlar la hidratación y el ajuste.
- Se necesitan técnicas analíticas avanzadas para resolver especies moleculares complejas en el cemento.
Objetivo del estudio:
- Para establecer las estructuras moleculares de los cementos anhidros e hidratados utilizando avanzada RMN en estado sólido.
- Para distinguir entre diferentes especies moleculares y seguir los cambios durante la hidratación y el ajuste del cemento.
Principales métodos:
- Utilizó una y dos dimensiones (2D) estado sólido (29) Si y (27) Al ángulo mágico girando RMN.
- Empleado T(1)-tiempo de relajación-y mediciones filtradas por desplazamiento químico-anisotropía en campos magnéticos muy altos (19 T).
- Espectro de RMN correlacionado con fluorescencia de rayos X para el análisis cuantitativo de especies de silicato y aluminato.
Principales resultados:
- Resolvió y asignó resonancias de varias fracciones de silicato y aluminato en espectros complejos de cemento.
- Especies de silicato y aluminato cuantificadas, cristalinas y desordenadas, tanto en cemento anhidro como en hidratado.
- Interacciones establecidas entre los grupos agua/hidroxilo y las especies específicas (27) Al y (29) Si en el cemento hidratado.
- Distinguidas especies de silicatos que contienen hierro, que muestran segregación de los componentes de silicato de calcio y aluminato durante la hidratación.
Conclusiones:
- La RMN de estado sólido proporciona información molecular detallada sobre la composición y la hidratación del cemento.
- Las características moleculares distintas de diferentes tipos de cemento (por ejemplo, Portland blanco frente a pozos de petróleo grises) se correlacionan con sus comportamientos de hidratación.
- Las metodologías avanzadas de RMN permiten la caracterización precisa de materiales cementicios.
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