| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Holt, Erika
VTT Technical Research Centre of Finland
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (13/13 displayed)
- 2020Characterization of Cebama low-pH reference concrete and assessment of its alteration with representative waters in radioactive waste repositoriescitations
- 2020Characterization of Cebama low-pH reference concrete and assessment of its alteration with representative waters in radioactive waste repositoriescitations
- 2020Contribution of the results of the CEBAMA project to decrease uncertainties in the Safety Case and Performance Assessment of radioactive waste repositoriescitations
- 2017Comparison of experimental and modelled pore solutions of low-pH Ordinary Portland Cement based mix designs
- 2017Development and demonstration of concrete for investigative deep borehole sealing at Olkiluoto nuclear repository site
- 2014Developing Low pH concrete for tunnel plugging structures in nuclear waste containment
- 2014Development of durable pervious concrete for Finland's stormwater management needs
- 2012Concrete durability based on coupled deterioration by frost, carbonation and chloride
- 2011Buffer component manufacturing by uniaxial compression method:Small scale
- 2011Buffer component manufacturing by uniaxial compression method
- 2006Use of gasification residues in compacted concrete paving blockscitations
- 2004Recent Finnish experience with environmentally-friendly and durable HPC
- 2004Implementing environmentally-friendly and durable concrete to Finnish practice
Places of action
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article
Characterization of Cebama low-pH reference concrete and assessment of its alteration with representative waters in radioactive waste repositories
Abstract
<p>Concretes, mortars and grouts are used for structural and isolation purposes in radioactive and nuclear waste repositories. For example, concrete is used for deposition tunnel end plugs, engineered barriers, mortars for rock bolting and injection grouts for fissure sealing. Despite of the materials anticipated functionality, it is extremely important to understand the long-term material behaviour in repository environments. A reference concrete and mortar for the Cebama project based on a cement, silica and blast furnace slag ternary blend were designed and characterized in different laboratories with multiple experimental methods (XRD, XAS at the Fe and Cl K-edges, SEM-EDX, <sup>29</sup>Si and <sup>27</sup>Al MAS-NMR, TG-DSC, MIP and Kerosene porosimetry) and techniques (punch strength tests). The reference concrete enabled comparison of results from different institutes and experimental techniques, unifying the individual results to more comprehensive body. The Cebama reference concrete and mortar were designed to have high durability and compatible formulation with respect to an engineered barrier system in clay or crystalline host-rocks, having pore solution pH significantly lower than traditional concretes. This work presents main results regarding their characterization and alteration in contact with representative waters present in radioactive waste repositories. Pore solution pH of the matured reference concrete was 11.4–11.6. The main hydrated phases were C–S–H and C-A-S-H gels with a Ca:Si ratio between 0.5 and 0.7 and an Al:Si ratio of 0.05. Minor phases were ettringite and hydrotalcite. Iron(III) could be in the C–S–H phases and no Cl-bearing solid phases were identified. Connected porosity and pore size distribution was characterized by MIP observing that, as expected, the size of the pores in the hydrated cement phases varies from the micro-to the nanoscale. Connected porosity of both materials were low. Compressive strength of the concrete was 115 MPa, corresponding to traditional high-performance concrete. Degradation of these materials in contact with different waters mainly produce their decalcification and enrichment in Mg for waters containing high amount of this element, like the clay waters.</p>