Research on swelling clays and bitumen as sealing materials for radioactive waste repositories
This report describes a programme of research to investigate the performance of composite seals incorporating adjacent blocks of swelling clay and bitumen. It is shown that the interaction of the materials can promote a self-sealing mechanism which prevents water penetration, even when defects are present in the bitumen layer. A review of the swelling properties of highly compacted bentonite and magnesium oxide is presented, and the characteristic sealing properties of bituminous materials are described. It is concluded that bentonite is the preferred candidate material for use in composite clay/bitumen seals for intermediate-level radioactive waste repositories. Magnesium oxide may have other sealing applications for high level waste repositories. A programme of laboratory experiments is described in which relevant swelling and intrusion properties of highly compacted bentonite blocks and the annealing characteristics of oxidised and hard-grade industrial bitumens are examined. The results of composite sealing experiments involving different water penetration routes are reported, and factors governing the mechanism of self-sealing are described.
Bibliographic Reference: EUR 13522 EN (1991) 145 pp., FS, ECU 12.50
ISBN: ISBN 92-826-2647-4
Record Number: 199110720 / Last updated on: 1994-12-02
Original language: en
Available languages: en