A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
29.Si cross-polarization magic-angle spinning NMR spectroscopy - an efficient tool for quantification of thaumasite in cement-based materials
29.Si(1.H) cross-polarization (CP) magic-angle spinning (MAS) NMR spectroscopy is a strong and reliable tool for quantification of thaumasite in cement-based materials. The most efficient method for quantifying thaumasite from 29.Si(1.H) CP/MAS NMR spectra is described and it is shown that the method allows detection of thaumasite contents below approximately 10 % wt with a relative precision of 15 % and contents above 10 % wt with a relative precision of 10 %. The applicability of 29.Si(1.H) CP/MAS NMR for quantification of thaumasite is demonstrated for different Portland cement pastes and shows that thaumasite contents as low as 0,2-0,5 % wt can be detected for cementitious systems with low concentrations of paramagnetic impurities. For a Portland cement containing various amounts of limestone dust and stored at 5 deg C in a MgSO4 solution, large quantities of thaumasite have been detected. Furthermore, the quantity of thaumasite is found to be less sensitive to the amount of added limestone dust. For samples of a Portland cement with a fixed content of limestone dust but different quantities of added gypsum, the increased contents of gypsum were observed to result in larger quantities of thaumasite after prolonged hydration.
29.Si cross-polarization magic-angle spinning NMR spectroscopy - an efficient tool for quantification of thaumasite in cement-based materials
29.Si(1.H) cross-polarization (CP) magic-angle spinning (MAS) NMR spectroscopy is a strong and reliable tool for quantification of thaumasite in cement-based materials. The most efficient method for quantifying thaumasite from 29.Si(1.H) CP/MAS NMR spectra is described and it is shown that the method allows detection of thaumasite contents below approximately 10 % wt with a relative precision of 15 % and contents above 10 % wt with a relative precision of 10 %. The applicability of 29.Si(1.H) CP/MAS NMR for quantification of thaumasite is demonstrated for different Portland cement pastes and shows that thaumasite contents as low as 0,2-0,5 % wt can be detected for cementitious systems with low concentrations of paramagnetic impurities. For a Portland cement containing various amounts of limestone dust and stored at 5 deg C in a MgSO4 solution, large quantities of thaumasite have been detected. Furthermore, the quantity of thaumasite is found to be less sensitive to the amount of added limestone dust. For samples of a Portland cement with a fixed content of limestone dust but different quantities of added gypsum, the increased contents of gypsum were observed to result in larger quantities of thaumasite after prolonged hydration.
29.Si cross-polarization magic-angle spinning NMR spectroscopy - an efficient tool for quantification of thaumasite in cement-based materials
29.Si CP/MAS NMR Spektroskopie - ein effizientes Werkzeug für die quantitative Bestimmung von Thaumasit in zement-basierten Materialien
Skibsted, J. (author) / Rasmussen, S. (author) / Herfort, D. (author) / Jakobsen, J. (author)
2002
9 Seiten, 4 Bilder, 2 Tabellen, 16 Quellen
Conference paper
Storage medium
English
| British Library Conference Proceedings | 2003