Investigation of swelling pressure of bentonite/claystone mixture in the full range of bentonite fraction

Zhixiong Zeng , Yu Jun Cui (1) , Feng Zhang , Nathalie Conil (2) , Jean Talandier (2)

1 navier umr 8205 - Laboratoire Navier
2 ANDRA - Agence Nationale pour la Gestion des Déchets Radioactifs

MX80 bentonite/Callovo-Oxfordian (COx) claystone mixture has been proposed as a sealing/backfilling material in a deep geological repository of radioactive waste in France. A good understanding of the swelling behaviour of this mixture is essential when evaluating the long-term performance of the repository. In this work, the swelling pressure of MX80 bentonite/COx claystone mixture was investigated by the constant-volume method for a full range of bentonite fraction. Results show that the swelling of claystone in the mixture can be inhibited by bentonite and its contribution to the global swelling pressure depends on the bentonite fraction. For the mixture with >70% bentonite, claystone behaves as an inert material, and its contribution to the global swelling pressure can be ignored. However, for the mixture with less bentonite, the swelling of claystone will significantly contribute to the global swelling pressure. A method was proposed allowing the swelling pressure of bentonite/claystone mixture to be predicted in the full range of bentonite fraction.

Mots clés: BENTONITE/CLAYSTONE MIXTURE; SWELLING PRESSURE; BENTONITE DRY DENSITY; INHIBITION EFFECT; PREDICTION METHOD

Mots clés: BENTONITE; ARGILE; MODELE PREDICTIF; INHIBITEUR

Domaines: Mécanique des matériaux [physics.class-ph]

Zhixiong Zeng, Yu Jun Cui, Feng Zhang, Nathalie Conil, Jean Talandier. Investigation of swelling pressure of bentonite/claystone mixture in the full range of bentonite fraction. Applied Clay Science, 2019, 178, 25 p. ⟨10.1016/j.clay.2019.105137⟩. ⟨hal-02499315⟩