Solid-state {sup 27}Al and {sup 29}Si NMR characterization of hydrates formed in calcium aluminate-silica fume mixtures

Journal Article · Fri Aug 15 00:00:00 EDT 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.03.026· OSTI ID:21128369

Pena, P; Rivas Mercury, J M ^[1]; Aza, A.H. de , ^[1]; Turrillas, X ^[2]; Sobrados, I; Sanz, J ^[3]

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1. Instituto de Ceramica y Vidrio, C.S.I.C., C/ Kelsen, 5, 28049 Cantoblanco-Madrid (Spain)
2. Instituto de Ciencias de la Construccion Eduardo Torroja, C.S.I.C., C/ Serrano Galvache, 4, 28032 Madrid (Spain)
3. Instituto de Ciencia de Materiales, C.S.I.C., C/ Sor Juana Ines de la Cruz, 3, 28049 Cantoblanco-Madrid (Spain)

Partially deuterated Ca{sub 3}Al{sub 2}(SiO{sub 4}){sub y}(OH){sub 12-4y}-Al(OH){sub 3} mixtures, prepared by hydration of Ca{sub 3}Al{sub 2}O{sub 6} (C{sub 3}A), Ca{sub 12}Al{sub 14}O{sub 33} (C{sub 12}A{sub 7}) and CaAl{sub 2}O{sub 4} (CA) phases in the presence of silica fume, have been characterized by {sup 29}Si and {sup 27}Al magic-angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopies. NMR spectroscopy was used to characterize anhydrous and fully hydrated samples. In hydrated compounds, Ca{sub 3}Al{sub 2}(OH){sub 12} and Al(OH){sub 3} phases were detected. From the quantitative analysis of {sup 27}Al NMR signals, the Al(OH){sub 3}/Ca{sub 3}Al{sub 2}(OH){sub 12} ratio was deduced. The incorporation of Si into the katoite structure, Ca{sub 3}Al{sub 2}(SiO{sub 4}){sub 3-x}(OH){sub 4x}, was followed by {sup 27}Al and {sup 29}Si NMR spectroscopies. Si/OH ratios were determined from the quantitative analysis of {sup 27}Al MAS-NMR components associated with Al(OH){sub 6} and Al(OSi)(OH){sub 5} environments. The {sup 29}Si NMR spectroscopy was also used to quantify the unreacted silica and amorphous calcium aluminosilicate hydrates formed, C-S-H and C-A-S-H for short. From {sup 29}Si NMR spectra, the amount of Si incorporated into different phases was estimated. Si and Al concentrations, deduced by NMR, transmission electron microscopy, energy dispersive spectrometry, and Rietveld analysis of both X-ray and neutron data, indicate that only a part of available Si is incorporated in katoite structures. - Graphical abstract: Transmission electron micrograph of CaAl{sub 2}O{sub 4}-microsilica mixture hydrated at 90 deg. C for 31 days showing a cubic Ca{sub 3}Al{sub 2.0{+-}}{sub 0.2}(SiO{sub 4}){sub 0.9{+-}}{sub 0.2}(OH){sub 1.8} crystal surrounded by unreacted amorphous silica spheres.

• OSTI ID: 21128369
• Journal Information: Journal of Solid State Chemistry, Vol. 181, Issue 8; Other Information: DOI: 10.1016/j.jssc.2008.03.026; PII: S0022-4596(08)00160-6; Copyright (c) 2008 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINATES
ALUMINIUM HYDROXIDES
ALUMINIUM OXIDES
ALUMINIUM SILICATES
CALCIUM OXIDES
CALCIUM SILICATES
CEMENTS
CONCRETES
GIBBSITE
HYDRATES
MIXTURES
NEUTRON DIFFRACTION
NMR SPECTRA
NUCLEAR MAGNETIC RESONANCE
SILICON OXIDES
SPECTROSCOPY
TRANSMISSION ELECTRON MICROSCOPY