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Volume change behaviour of some geomaterials under combined influence of freeze-thaw and wet-dry cycles: An experimental investigation

Al-Hussaini, Osama 2017. Volume change behaviour of some geomaterials under combined influence of freeze-thaw and wet-dry cycles: An experimental investigation. PhD Thesis, Cardiff University.
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Abstract

Climate change has led to more extreme weather during the last decades. Seasonally hot weather regions have experienced harsh winters. Similarly, the global warming has contributed to raising the mean summer temperature in the cold regions. Geomaterials in various engineering applications are expected to experience such changes in the weather patterns and may undergo freezing, thawing, wetting and drying processes. This thesis presents an experimental study of the one-dimensional volume change behaviour of some geomaterials under the combined influence of freeze-thaw and wet-dry cycles. Laboratory tests were carried out on three selected materials (Speswhite kaolin, Pegwell Bay soil and cement kiln dust). A custom-made test set up was used to carry out the laboratory tests that enabled performing the required tests involving freezing, thawing, drying and wetting processes. Initially saturated slurried materials and compacted materials were subjected to freezing and thawing processes to study frost heave and thaw settlement. Compacted materials were taken through several wet-dry cycles and then exposed to freezing and thawing processes to study the impact of intermittent freeze-thaw cycles on the volume change behaviour of the materials. Similarly, compacted materials were subjected to an increasing number of freeze-thaw-wet-dry cycles to study the combined influence of various processes on the volume change behaviour of the materials. Compacted materials exhibited higher magnitudes of frost heave than initially saturated slurried materials. The swelling and shrinkage strains of compacted materials decreased with an increasing number of wet-dry cycles and attained an equilibrium at which the strains remained very similar. Intermittent freeze-thaw cycles were found to destabilize the equilibrium strain that was achieved during the previous wet-dry cycles; however, a new equilibrium in terms of the vertical strain was attained by the materials with an increasing number of wet-dry cycles. The materials having a history of being exposed to several wet-dry cycles exhibited a higher frost heave, a higher segregation potential and a greater magnitude of thaw settlement as compared to the same materials but without any cyclic wet-dry history. Upon subjected to an increasing number of wet-freeze-thaw-dry cycles, the materials exhibited uprising movement accompanied by strain accumulation prior to attaining an equilibrium at which the vertical strains associated with wetting, freezing, thawing and drying processes were found to be dissimilar; however, the sum of swelling deformation and frost heave was found to be equal to the sum of thaw settlement and shrinkage deformation.

Item Type: Thesis (PhD)
Date Type: Submission
Status: Unpublished
Schools: Engineering
Uncontrolled Keywords: Freeze-thaw Cycles; Wet-Dry Cycles; Colum change; Compacted; Weathering effects; Speswhite kaolin.
Date of First Compliant Deposit: 20 April 2018
Last Modified: 20 Apr 2018 13:42
URI: http://orca-mwe.cf.ac.uk/id/eprint/110778

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