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Title
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A pore-scale study of fracture dynamics in rock using X-ray micro-CT under ambient freeze-thaw cycling
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Author
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Abstract
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| Freeze-thaw cycling stresses many environments which include porous media such as soil, rock and concrete. Climate change can expose new regions and subject others to a changing freeze-thaw frequency. Therefore, understanding and predicting the effect of freeze-thaw cycles is important in environmental science, the built environment and cultural heritage preservation. In this paper, we explore the possibilities of state-of-the-art micro-CT in studying the pore scale dynamics related to freezing and thawing. The experiments show the development of a fracture network in a porous limestone when cooling to -9.7 degrees C, at which an exothermal temperature peak is a proxy for ice crystallization. The dynamics of the fracture network are visualized with a time frame of 80 s. Theoretical assumptions predict that crystallization in these experiments occurs in pores of 6-20.1 nm under transient conditions. Here, the crystallization-induced stress exceeds rock strength when the local crystal fraction in the pores is 4.3%. The location of fractures is strongly related to preferential water uptake paths and rock texture, which are visually identified. Laboratory, continuous X-ray micro-CT scanning opens new perspectives for the pore-scale study of ice crystallization in porous media as well as for environmental processes related to freeze-thaw fracturing. |
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Language
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English
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Source (journal)
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Environmental science and technology / American Chemical Society. - Easton, Pa
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Publication
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Easton, Pa
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2015
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ISSN
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0013-936X
[print]
1520-5851
[online]
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DOI
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10.1021/ES505738D
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Volume/pages
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49
:5
(2015)
, p. 2867-2874
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ISI
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000350611100038
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Pubmed ID
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25683464
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Full text (Publisher's DOI)
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