Effect of hydrating water on the physical characteristics and diffusion release of CsNO(3) immobilized in cement
The effect of the preparation procedure (variable amounts of hydrating water) on the leachability of a soluble contaminant (CsNO(3)) from cement samples immersed in water are considered, together with the physical characteristics of cement samples such as density, pore volume and compressive strength. Leach tests of cement specimens containing 2 w/w CsNO(3), prepared at different water-to-cement ratios (W/C 0.35, 0.40, 0.45 and 0.55) were cured at 60 C, 98% RH, for 11 days. The standard ISO procedure was used to follow the kinetics for the Cs(+), NO(3)(-) and Ca(2+) releases from cement right cylinders, 20mm in diameter and 20 mm high, leached in water at a solid surface-to-liquid volume S/V = 0.1/cm. The variation of the cumulative fraction release (CFR) with time in days indicates that the leaching of soluble elements such as NO(3)(-) and caesium follows a diffusion mechanism. The CFR values were found to depend on a porosity factor dependent on the ratio of the total porosity of cement at the W/C considered to the porosity at W/C = 0.35. A diffusion coefficient, D(e) = 1.4x1.0E-7cm2/s, calculated from the values of the cumulative fraction release at 50 C with W/C = 0.35, confirms previous results obtained on cement samples containing CsNO(3) prepared under the same conditions.
Bibliographic Reference: Paper presented: Stabilization/Solidification Hazardous, Radioactive, Mixed Wastes, Williamsbourg, Virginia (US), May 29 - June 1, 1990
Availability: Available from (1) as Paper EN 35484 ORA
Record Number: 199011248 / Last updated on: 1994-12-01
Original language: en
Available languages: en