Reaction and Alteration of Mudstone with Ordinary Portland Cement and Low Alkali Cement Pore Fluids
| Autor: | Yukio Tachi, Keith Bateman, Yuki Amano, Mitsuru Kubota, Yuji Ohuchi |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Cement
LAC 010504 meteorology & atmospheric sciences Precipitation (chemistry) Chemistry alkaline leachate Radioactive waste Geology 010502 geochemistry & geophysics Geotechnical Engineering and Engineering Geology Alkali metal Mineralogy 01 natural sciences law.invention Portland cement law Environmental chemistry radioactive waste Cementitious Leachate cement-clay interaction Dissolution OPC 0105 earth and related environmental sciences QE351-399.2 |
| Zdroj: | Minerals, Vol 11, Iss 588, p 588 (2021) Minerals Volume 11 Issue 6 |
| Popis: | The construction of a repository for the geological disposal of radioactive waste will utilize cement-based materials. Following closure, resaturation will result in the development of a highly alkaline porewater. The alkaline fluid will migrate and react with host rock, producing a chemically disturbed zone (CDZ) around the repository. To understand how these conditions may evolve, a series of batch and flow experiments were conducted with Horonobe mudstone and fluids representative of the alkaline leachates expected from a cementitious repository. Both ordinary Portland cement (OPC) and low alkali cement (LAC) leachates were examined. The impact of the LAC leachates was more limited than the OPC leachates, with experiments using the LAC leachate showing the least reaction and lowest long-term pH of the different leachate types. The reaction was dominated by primary mineral dissolution, and in the case of OPC leachates, precipitation of secondary calcium-silicate-hydrate (C-S-H) phases. Flow experiments revealed that precipitation of the secondary phases was restricted to close to the initial contact zone of the fluids and mudstone. The experimental results demonstrate that a combination of both batch and flow-through experiments can provide the insights required for the understanding of the key geochemical interactions and the impact of transport. |
| Databáze: | OpenAIRE |
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