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The U phase formation in cement-based systems containing high amounts of Na2SO4

✍ Scribed by G. Li; P. Le Bescop; M. Moranville

Publisher
Elsevier Science
Year
1996
Tongue
English
Weight
531 KB
Volume
26
Category
Article
ISSN
0008-8846

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✦ Synopsis

Simulated cemented low level wastes containing high amounts of Na,SO, (10 -15%) were examined with respect to the mineralogy of the solid phases, chemical composition of the interstitial aqueous phase and immersion behaviour in water. All results reveal the formation of a mineral called U phase, first observed by Dosch and zur Strassen in 1967, and its deleterious effects on the samples immersed in water. It appears that this phase can form only at very high alkaline concentration, not compatible with traditional cement paste. Two possible degradation mechanisms associated with the U phase are proposed which are to be elucidated in further works.

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