Quantification of water content across a cement-clay interface using high resolution neutron radiography

Shafizadeh, A; Gimmi, Thomas; Van Loon, L; Kaestner, A; Lehmann, E; Mäder, Urs; Churakov, Sergey (2015). Quantification of water content across a cement-clay interface using high resolution neutron radiography. Physics Procedia, 69, pp. 516-523. Elsevier 10.1016/j.phpro.2015.07.073

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In many designs for radioactive waste repositories, cement and clay will come into direct contact. The geochemical contrast between cement and clay will lead to mass fluxes across the interface, which consequently results in alteration of structural and transport properties of both materials that may affect the performance of the multi-barrier system. We present an experimental approach to study cement-clay interactions with a cell to accommodate small samples of cement and clay. The cell design allows both in situ measurement of water content across the sample using neutron radiography and measurement of transport parameters using through-diffusion tracer experiments. The aim of the high- resolution neutron radiography experiments was to monitor changes in water content (porosity) and their spatial extent. Neutron radiographs of several evolving cement-clay interfaces delivered quantitative data which allow resolving local water contents within the sample domain. In the present work we explored the uncertainties of the derived water contents with regard to various input parameters and with regard to the applied image correction procedures. Temporal variation of measurement conditions created absolute uncertainty of the water content in the order of ±0.1 (m3/m3), which could not be fully accounted for by correction procedures. Smaller relative changes in water content between two images can be derived by specific calibrations to two sample regions with different, invariant water contents.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences
08 Faculty of Science > Institute of Geological Sciences > Rock-Water Interaction

UniBE Contributor:

Gimmi, Thomas; Mäder, Urs and Churakov, Sergey

Subjects:

500 Science > 550 Earth sciences & geology
500 Science > 530 Physics

ISSN:

1875-3892

Publisher:

Elsevier

Language:

English

Submitter:

Thomas Gimmi

Date Deposited:

09 Nov 2015 11:31

Last Modified:

01 Mar 2016 13:18

Publisher DOI:

10.1016/j.phpro.2015.07.073

BORIS DOI:

10.7892/boris.72547

URI:

https://boris.unibe.ch/id/eprint/72547

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