| Autor: |
J. S. Ceballos-Ruano, Teobald Kupka, Marios A. Ioannidis, C. Hansson, J. W. Benson, M. M. Pintar, D. W. Nicoll |
| Rok vydání: |
2002 |
| Předmět: |
|
| Zdroj: |
Journal of Applied Physics. 91:6588 |
| ISSN: |
0021-8979 |
| DOI: |
10.1063/1.1467631 |
| Popis: |
Nuclear magnetic resonance (NMR) experiments monitoring the imbibition (sorption) and diffusion of water into white cement paste are reported. The sample was a 1.3 cm long cylinder (6 mm o.d.) of hardened ordinary white cement paste, with a water/cement ratio of 0.42 containing 0.5% Ca(NO2)2 and 2% NaCl. Water proton magnetization and T2 values were obtained as functions of time. Imbibition of H2O and diffusion of H2O and D2O were monitored with 1H NMR at 26 and 30 MHz. The countercurrent water imbibition experiments revealed a two-stage process. A rapid uptake of water, involving about 85% of the total, took place in about 45 min. Maximum saturation was reached in about 2 days. Both stages of the process were well described by a nonlinear diffusion-like equation. Diffusion of both H2O and D2O was characterized by a single diffusion coefficient. The diffusion coefficient for H2O and D2O, derived by fitting the data to the diffusion equation, is well predicted by D0/(Fφ). |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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