FREEZE-THAW BEHAVIOR OF GYPSEOUS SOIL

This research work studied the influence of freeze-thaw (F-T) cycles and gypsum percent on the mechanical properties and durability of clayey soil. Different amount of gypsum percent (varied between 0-25%) was added to the clayey soil and subjected to 12 F-T cycles. The unconfined compressive strength UCS, P-wave velocity, gas permeability, pore size distribution and volume changes properties were measured for both un-cycled and F-T cycled samples. The tests results presented that the UCS, gas permeability and porosity values of samples influenced by F-T cycles. These values depend considerably on the amounts of gypsum percent and F-T cycles. Further, changes in soil porosity were observed during F-T cycles due to ice lenses formation and cracks propagation. Finally, the UCS, gas permeability and volume change values have been proposed to be used to evaluate extent of durability of soil samples.