Freezing-induced bulk soil volume changes

The volumetric expansion accompanying the phase transition from water to ice does not always cause structural deterioration in soil, as at low water contents the empty pore volume of the soil may be sufficient to contain this expansion. The objective of this study was to investigate the volume change in soils of varying clay contents and initial water contents during the freezing process. Volume change upon freezing was measured for seven soils with clay contents ranging from 0.11 to 0.75 kg kg –1 . Curve fitting revealed percent saturation levels corresponding to maximum shrinkage, zero volume change and maximum expansion. Curves for all soils exhibited similar shapes, composed of zones dominated by volumetric decreases at values less that 63 to 70% saturation, and expansion at percent saturations above this level. Zero volume change occurred at percent saturations of 74 to 90%. Clay content was found to control the maximum amount of shrinkage, with greater shrinkage in soils with higher clay contents. Bulk soil volume decreases occur in non-rigid clay containing soils due to desiccation and shrinkage when frozen at low water contents.Key words: Volume change, soil freezing, cla