In-situ interaction between cement and clay: Implications for geological disposal

A. Sneyers, M. Paul, M. Tyrer, F. P. Glasser, J. Fays, P. Van Iseghem

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)123-129
Number of pages7
JournalMaterials Research Society Symposium Proceedings
Volume663
DOIs
Publication statusPublished - 2000
Externally publishedYes

Fingerprint

disposal
cements
clays
Cements
Clay
boom
interactions
Radioactive Waste
radioactive wastes
Radioactive wastes
calcium
Calcium
waste management
porosity
clay
Calcium Carbonate
Calcite
Electron probe microanalysis
electron probes
Silicon

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this

In-situ interaction between cement and clay : Implications for geological disposal. / Sneyers, A.; Paul, M.; Tyrer, M.; Glasser, F. P.; Fays, J.; Van Iseghem, P.

In: Materials Research Society Symposium Proceedings, Vol. 663, 2000, p. 123-129.

Research output: Contribution to journalArticle

Sneyers, A. ; Paul, M. ; Tyrer, M. ; Glasser, F. P. ; Fays, J. ; Van Iseghem, P. / In-situ interaction between cement and clay : Implications for geological disposal. In: Materials Research Society Symposium Proceedings. 2000 ; Vol. 663. pp. 123-129.
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