Ageing effects in a compacted bentonite: a microstructure approach

• DOI: 10.1680/geot.2006.56.5.291
• Publication Date: 2006-07-07T13:20:51Z
• Authors: P. Delage; D. Marcial; Y. J. Cui; X. Ruiz
• Keywords: Bentonite

It is suspected that the as-compacted state of heavily compacted clays used as possible engineered barriers for nuclear waste disposal time dependent, and further change may occur in material, even at constant water content density. This paper presents an investigation time-dependent microstructure changes MX80 clay bentonite various dry densities contents. Microstructure based on mercury intrusion pore size distribution measurements scanning electron microscopy (SEM). Results obtained by other researchers using X-ray diffraction low angles are also used. Statically samples were kept volume periods (1, 30 90 days) prior to SEM micro-structure investigation. A significant with was observed, characterised a decrease inter-aggregate porosity increase very thin not intruded (r < 3·7 nm). The former observation related filling larger pores exfoliation, latter aggregates within smectite particles when suction reduced. These interpreted light carried out similar low-angle diffraction. Changes inside governed progressive placement interlayer molecules together subdivision particles, which gives rise interparticle develops aggregates.