Time-resolved porosity changes at cement-clay interfaces derived from neutron imaging

Shafizadeh, A; Gimmi, T.; Van Loon, LR; Kaestner, AP; Mäder, U. K.; Churakov, S. V. (2020). Time-resolved porosity changes at cement-clay interfaces derived from neutron imaging. Cement and concrete research, 127, p. 105924. Elsevier 10.1016/j.cemconres.2019.105924

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Interfaces between cement and clay are common in engineered barrier systems for the underground disposal of radioactive waste. The geochemical contrast between clay and cement leads to alterations of both materials following dissolution and precipitation reactions. Porosity is a key parameter for, and a key outcome of, such reactive transport. Here we report on the evolution of porosity within small samples made from ordinary portland cement and Na montmorillonite. Water contents, a proxy for porosity in saturated samples, were derived from neutron imaging. Specific calibration procedures were developed to account for multiple scattering effects. An increase in cement porosity was observed propagating similar to 2 mm away from the interface within 600 days, and a considerable decrease in clay porosity within similar to 2 mm. Our experiments provide unique information on the dynamics of the processes up to nearly two years. The data set provides valuable input to better constrain reactive transport models.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Institute of Geological Sciences > Mineralogy
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

ISSN:

0008-8846

Publisher:

Elsevier

Language:

English

Submitter:

Thomas Gimmi

Date Deposited:

03 Apr 2020 14:05

Last Modified:

05 Apr 2020 02:50

Publisher DOI:

10.1016/j.cemconres.2019.105924

BORIS DOI:

10.7892/boris.142920

URI:

https://boris.unibe.ch/id/eprint/142920

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