CHEMO-MECHANICAL COUPLINGS IN COMPACTED ARGILLITE SUBMITTED TO HIGH-PH ENVIRONMENT
In the French concept of deep nuclear wastes repository, the galleries should be backfilled with excavated argillite after the site exploitation period. After several thousands of years, the degradation of the concrete lining of the galleries will generate alkaline fluid (pH > 12) that will diffuse through the backfill. The object of the paper is to describe the influence of such solute diffusion on the microstructure and the mechanical behaviour of compacted argillite. Saturated-portlandite water was circulated through compacted samples for 3, 6 and 12 months at 20 or 60°C. The microstructure before and after fluid circulation were determined with mercury intrusion porosimetry. Since it is planned to introduce additives (bentonite or lime) in the remoulded argillite to backfill the deep galleries, such mixtures were also studied. The results showed that the influence of the alkaline fluid on the properties of the argillite is a function of the nature of the additive. The pure argillite underwent slight modifications that can be related to a limited dissolution of its clayey particles. Conversely, intense alteration of the bentonite-argillite mixture was observed. Lime addition improved the mechanical characteristics of the argillite through the precipitation of cementitious compounds.
chemo-mechanical couplings alkaline plume argillite microstructure shear strength
O. Cuisinier F. Masrouri
LAEGO, Nancy-Universite, France
国际会议
上海
英文
104-111
2009-08-24（万方平台首次上网日期，不代表论文的发表时间）