title: A pore-scale study of fracture dynamics in rock using X-ray micro-CT under ambient freeze-thaw cycling.
abstract: 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 °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.
authors: UGCT-Department of Geology and Soil Science, Faculty of Sciences, Ghent University , Krijgslaan 281/S8, 9000 Ghent, Belgium.
authors: Tim
authors: T
authors: De Kock
authors: Marijn A
authors: MA
authors: Boone
authors: Thomas
authors: T
authors: De Schryver
authors: Jeroen
authors: J
authors: Van Stappen
authors: Hannelore
authors: H
authors: Derluyn
authors: Bert
authors: B
authors: Masschaele
authors: Geert
authors: G
authors: De Schutter
authors: Veerle
authors: V
authors: Cnudde
mesh_terms: D057231:Climate Change; D003460:Crystallization; D005615:Freezing; D007053:Ice; D016062:Porosity; D012987:Soil; D013696:Temperature; D014867:Water; D055114:X-Ray Microtomography / Q000379:methods*
chemical_list: D007053:Ice; D012987:Soil; D014867:Water