Freezing in saturated bentonite – A thermodynamic approach

A homogeneous and isotropic model of pressure response in saturated bentonite due to temperature changes is presented. The model predicts minor changes of swelling pressure with temperature above 0 °C, in accordance with reported measurements. Below 0 °C, however, a huge temperature dependence is predicted. This behavior can be directly related to the entropy difference of clay water and water in ice phase, and is shown to be completely analogous to the effect of freezing point depression in ordinary salt solutions. Swelling pressure measurements are also reported, which confirm the effect.