The extent and the consequences of interactions between cementitious materials used in radioactive waste management and clay host rock are described. In-situ tests were performed on seven cement formulations representing materials applied in repository construction, for backfilling or for solidification of radioactive waste. Samples were exposed to realistic repository conditions of the Boom Clay Formation in the HADES underground laboratory. Chemical, physical and mineralogical changes across the cement-clay interface were identified by combined observations from Electron Probe Microanalysis, Infrared microscopy and X-Ray powder diffraction. Significant interactions in both the cement and the clay part were found in a zone extending up to several hundreds of microns. The most prominent features are (1) leaching of cement with loss of calcium and/or silicon; (2) development of a calcium-rich zone in Boom Clay close to or at contact; (3) the formation of a contact zone marked by the precipitation of a (hydrated) magnesium aluminate phase; (4) reduction in apparent porosity of initially porous/permeable materials and (5) precipitation of calcite within the cement. This elemental exchange tends to diminish pH and reduce the buffering capacity of the cement. Although hydroxide will diffuse into the clay, the development of an extensive alkaline halo in the surrounding clay is unlikely owing to the buffering capacity of the Boom Clay pore water.
This is a preview of subscription content, access via your institution.
We’re sorry, something doesn't seem to be working properly.
Please try refreshing the page. If that doesn't work, please contact support so we can address the problem.
A. Sneyers, J. Marivoet, P. Van Iseghem. Transactions of the “2nd International Topical Meeting on Research Reactor Fuel Management”, 29-31 March 1998, Bruges, Belgium. European Nuclear Society, Bern, p. 119–123 (1998).
A. Sneyers, S. Labat, P. Van Iseghem, M. Paul, E.E. Lachowski, F.P. Glasser. Ceramic Transactions, v.107, p. 109–206 (1999).
F.P. Glasser (Editor). ‘Barrier performance of cements and concretes’. Report to be published by the European Commission in the EUR-series.
A. Dierckx, A. Boom Clay in situ porewater chemistry. SCK•CEN report BLG-734 (1997).
D. Read, F.P. Glasser, A. Sneyers. Paper submitted to Advances in Cement Research.
About this article
Cite this article
Sneyers, A., Paul, M., Tyrer, M. et al. In-Situ Interaction between Cement and Clay: Implications for Geological Disposal. MRS Online Proceedings Library 663, 123 (2000). https://doi.org/10.1557/PROC-663-123