Elevated temperature (hydrothermal) stability of cementitious sealants for a deep geological repository in tuff
Grout formulations have been investigated in Nevada Nuclear Waste Storage Investigations Project, for possible nuclear waste repository sealing applications focused in the Yucca Mountain Area (in welded tuff). A shrinkage compensated cement was chemically modified with siliceous reactants to enhance...
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Veröffentlicht in: | Waste management (Elmsford) 1989, Vol.9 (4), p.253-259 |
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Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Grout formulations have been investigated in Nevada Nuclear Waste Storage Investigations Project, for possible nuclear waste repository sealing applications focused in the Yucca Mountain Area (in welded tuff). A shrinkage compensated cement was chemically modified with siliceous reactants to enhance the chemical compatibility with a siliceous tuff. Fluids in contact with the grouts were measured at 150 °C and 200 °C, and the solids were characterized. Well-crystallized Al-substituted tobermorite and truscottite were observed, and sometimes xonotlite as dominant cementitious phases. Comparisons of solid phases and solution phases are made with a second grout incorporating siliceous modifiers in a Class H cement. Exposures to 150 °C hydrothermal conditions have not produced significant detrimental mechanical behavior of the seal material. The thermal decomposition of ettringite, an expansive calcium sulfate aluminate hydrate, resulted in a small increase in the porosity of the grout, but on a very small fine scale. |
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ISSN: | 0956-053X 1879-2456 |
DOI: | 10.1016/0956-053X(89)90409-1 |