Direct observation of the moisture distribution in calcium aluminate cement and hydratable alumina‐bonded castables during first‐drying: An NMR study
| Autor: | Leo L Pel, Olaf C. G. Adan, Ahmed J. Barakat, Olaf Krause |
|---|---|
| Přispěvatelé: | Transport in Permeable Media, EIRES Systems for Sustainable Heat |
| Rok vydání: | 2019 |
| Předmět: |
Phase transition
Materials science Silica fume Aluminate chemistry.chemical_element 02 engineering and technology Calcium 01 natural sciences chemistry.chemical_compound porous media 0103 physical sciences Materials Chemistry Composite material 010302 applied physics Cement first-drying technology industry and agriculture Atmospheric temperature range equipment and supplies 021001 nanoscience & nanotechnology high-temperature NMR phase transitions castables chemistry Permeability (electromagnetism) Ceramics and Composites 0210 nano-technology Porous medium |
| Zdroj: | Journal of the American Ceramic Society, 103(3), 2101-2113. Wiley-Blackwell |
| ISSN: | 1551-2916 0002-7820 |
| DOI: | 10.1111/jace.16814 |
| Popis: | The drying behavior for various calcium aluminate cement and hydratable alumina-bonded refractory castables was investigated in the first-drying temperature range (100°C-300°C). Using a specialized high-temperature Nuclear Magnetic Resonance setup, we were able to directly and nondestructively measure the spatially and temporally resolved moisture distribution, while simultaneously measuring the temperature distribution as well. These measurements show that the drying front position is a linear function of time, which can be explained on the basis of a simplified model where only vapor transport is considered. Based on the measurements and the model, one can directly determine the permeability at high temperatures. Moreover, the results demonstrate that the drying front speed and temperature strongly correlates with the control of key material parameters (eg, water demand, binder content, etc). In particular, microsilica fume-containing low-cement castables displayed the highest vapor pressures, while regular castables generated the lowest vapor pressures reflecting the permeability of these materials. |
| Databáze: | OpenAIRE |
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