A talc-based cement-poor concrete for sealing boreholes in rock
2013 (English)In: Engineering, ISSN 1947-3931, E-ISSN 1947-394X, Vol. 5, no 3, 251-267 p.Article in journal (Refereed) Published
Deep investigation boreholes in crystalline rock for site selection of repositories for high-level radioactive waste are proposed to be sealed by installing a series of dense concrete and clay plugs. These should prevent radionuclides from leaking canisters at depth to migrate to the biosphere through the holes. The concrete seals will be installed where the holes intersect water-bearing fracture zones to serve as stable and low-permeable supports for adjacent clay plugs. Low porosity and microstructural stability must be guaranteed for many thousands of years and ordinary Portland cement with organic superplastizer will not fulfil the requirements since the high pH will cause degradation of contacting clay and the organic additive can produce colloids with a capacity to carry radionuclides up to the biosphere. Very cement-poor concrete (<8 %) based on low-pH cement and with talc as plasticizer is an option but it matures more slowly, which requires that the construction of seals is made so that sufficient bearing capacity for carrying overlying clay seals is reached.
Place, publisher, year, edition, pages
2013. Vol. 5, no 3, 251-267 p.
Clay, Concrete, Ductility, Strength, Superplasticizers, Talc, Civil engineering and architecture - Geoengineering and mining engineering
Samhällsbyggnadsteknik och arkitektur - Geoteknik och gruvteknik
Research subject Soil Mechanics
IdentifiersURN: urn:nbn:se:ltu:diva-15658DOI: 10.4236/eng.2013.53036Local ID: f32796a5-c272-4071-9fb7-6adb5a27100bOAI: oai:DiVA.org:ltu-15658DiVA: diva2:988633
Validerad; 2013; 20130104 (mohhat)2016-09-292016-09-29Bibliographically approved