2024-03-29T02:27:55Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/199332018-06-19T11:57:10Zcom_10261_23com_10261_3col_10261_276
00925njm 22002777a 4500
dc
Pena, Pilar
author
Rivas-Mercury, J. M.
author
Aza Moya, Antonio H. de
author
Turrillas, Xabier M.
author
Sobrados, Isabel
author
Sanz Lázaro, Jesús
author
2008-08
Partially deuterated Ca3Al2(SiO4)y(OH)12−4y–Al(OH)3 mixtures, prepared by hydration of Ca3Al2O6 (C3A), Ca12Al14O33 (C12A7) and CaAl2O4 (CA) phases in the presence of silica fume, have been characterized by 29Si and 27Al magic-angle spinning–nuclear magnetic resonance (MAS–NMR) spectroscopies. NMR spectroscopy was used to characterize anhydrous and fully hydrated samples. In hydrated compounds, Ca3Al2(OH)12 and Al(OH)3 phases were detected. From the quantitative analysis of 27Al NMR signals, the Al(OH)3/Ca3Al2(OH)12 ratio was deduced. The incorporation of Si into the katoite structure, Ca3Al2(SiO4)3−x(OH)4x, was followed by 27Al and 29Si NMR spectroscopies. Si/OH ratios were determined from the quantitative analysis of 27Al MAS–NMR components associated with Al(OH)6 and Al(OSi)(OH)5 environments. The 29Si 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 29Si 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.
Journal of Solid State Chemistry 181(8): 1744-1752 (2008)
0022-4596
http://hdl.handle.net/10261/19933
10.1016/j.jssc.2008.03.026
Cement and concretes
Si–hydrogarnet
Gibbsite
Al MAS–NMR
Si MAS–NMR
Neutron diffraction
Solid-state 27Al and 29Si NMR characterization of hydrates formed in calcium aluminate–silica fume mixtures