Hardening of clayey soil blocks during freezing and thawing cycles

Abstract Considering the lack of references dealing with the behaviour of clayey soil blocks subjected to freezing–thawing cycles, exploratory work has been carried out on such blocks to study the effects of freezing–thawing cycles on their mechanical properties. As the blocks were not stabilized, the procedures conventionally applied for freezing–thawing cycles, in which the samples are immersed, were adapted to this case of study: the specimens were humidified by placing them in a moist environment for 1 week (20 °C and 95% RH (relative humidity)) and were then subjected to freezing–thawing cycles without any re-humidification between cycles. The variations of weight and compressive wave velocity showed that freezing–thawing cycles led to the desiccation of the samples. The consequences of these cycles on the characteristics of the soil blocks were thus those of a conventional desiccation of specimens and, in particular, their hardening. This hardening was highlighted by the study of the mechanical characteristics of the clayey soil blocks (compressive strength and modulus).