Natural abundance high field 43Ca solid state NMR in cement science

Abstract

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1039/c000353kPhysical Chemistry Chemical Physics, 12, pp. 6961-6969, 2010-06-01 Natural abundance high field 43Ca NMR solid state NMR in cement science Moudrakovski, I.; Alizadeh, R.; Beaudoin, J. J. The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42Les renseignements dans ce document sont protégés par la Loi sur le droit d'auteur, par les lois, les politiques et les règlements du Canada et des accords internationaux. Ces dispositions permettent d'identifier la source de l'information et, dans certains cas, d'interdire la copie de documents sans permission écrite. Pour obtenir de plus amples renseignements : http://lois.justice.gc.ca/fr/showtdm/cs/C-42 Natural abundance high field 43 Ca solid state NMR in cement sciencew This work is a systematic attempt to determine the possibilities and the limitations of the 43 Ca high field solid state NMR in the study of cement-based materials. The low natural abundance (0.135%) and small gyromagnetic ratio of 43 Ca present a serious challenge even in a high magnetic field. The NMR spectra of a number of cement compounds of known structure and composition are examined. The spectra of several phases important in cement science, e.g., anhydrous beta di-calcium silicate (b-C 2 S) and tri-calcium (C 3 S) silicate were obtained for the first time and the relation of spectroscopic and structural parameters is discussed. The method was also applied to the hydrated C 3 S and synthetic calcium silicate hydrates (C-S-H) of different composition in order to understand the state of calcium and transformations in the structure during hydrolysis. The spectra of hydrated C 3 S reveals a calcium environment similar to that of the C-S-H samples and 11 Å Tobermorite. These observations support the validity of using layered crystalline C-S-H systems as structural models for the C-S-H that forms in the hydration of Portland cement.

A multinuclear solid-state magnetic resonance and GIPAW DFT study of anhydrous calcium chloride and its hydrates

“…It is immediately clear that the observed 35/37 Cl SSNMR line shapes and EFG tensor parameters are inconsistent with the prior literature account for CaCl 2 . 46 The presently measured C Q ( 35 Cl) value of 8.82 (8) MHz is more than twice as large as the values observed for other anhydrous and hydrated group 2 metal chlorides. 44,46,69 This is primarily attributed to the arrangement of the Ca 2+ ions within the first coordination sphere of each chloride, which forms a distorted trigonal plane.…”

“…[4][5][6] These tensors are important SSNMR observables, and a number of recent studies have illustrated that magnetic shielding and EFG tensor calculations using GIPAW DFT can provide additional insights in the study of a variety of chemical systems. [7][8][9][10][11][12][13][14][15][16][17] There is an increasing interest in "NMR crystallography", which pertains to obtaining molecular-level and crystal structure information for solid materials using SSNMR data. 18 Although there have been a number of exciting recent advances in this area of research, 6,[19][20][21][22][23][24][25] one cannot currently convert SSNMR data into a unique solid-state structure in a completely generalized manner.…”

Compositional Evolution of Calcium Silicate Hydrate (C–S–H) Structures by TotalX‐Ray Scattering

“…Studies by Moudrakovski et al 39 using 43 Ca NMR showed that there is little change in the signal from Ca compared to tobermorite for C-S-Hs with C/S ratios of up to 1.5. While we find no significant change in the average Ca-O distance with C/S ratio in our X-ray PDFs, Gaussian fits to the peak reveal a systematic decrease in the average Ca coordination number.…”

“…Studies by Moudrakovski et al . using 43 Ca NMR showed that there is little change in the signal from Ca compared to tobermorite for C–S–Hs with C/S ratios of up to 1.5.…”

Calcium-43 chemical shift and electric field gradient tensor interplay: a sensitive probe of structure, polymorphism, and hydration

“…1a), the 43 Ca EFG tensor must possess axial symmetry (i.e., the asymmetry parameter of the EFG tensor, Z Q , must equal 0), 75 which is interestingly in contrast with several earlier 43 Ca NMR measurements that report a small, albeit consistently nonzero Z Q ( 43 Ca) value. 33,35,76,77 Oxygen-17 SSNMR results have also been presented, 78,79 and while several measurements of the 43 Ca EFG tensor in Ca(OH) 2 have been conducted, we are not aware of any attempts to completely determine the calcium CSA tensor in this material, which also includes the measurement of the Euler angles relating the CSA and EFG tensor PASs.…”