A review of experimental and prediction methods for assessing the freezing characteristic curve of GCLs

Geosynthetic clay liners (GCLs) are an important part of composite hydraulic barriers in environmental projects, with recent applications in harsh conditions such as in Antarctica. To assure an adequate hydraulic performance of the GCL, the bentonite of the GCL needs to be well-hydrated. However, the sub-zero temperatures attained in Antarctica freeze the water inside the bentonite, and as a result, the hydration process stops with potential consequences on the hydraulic performance of the GCL. To predict the impact of freezing on GCL performance, it is essential to obtain the unsaturated freeze property functions (UFPFs) for the bentonite. The freezing characteristic curve (FCC), which relates the unfrozen water content with freezing temperatures, is the first of the UFPFs, and can be obtained experimentally or by prediction methods. This paper reviews the concepts leading to the determination of the FCC, its relationship with the other UFPFs and its importance for predicting GCL performance in cold regions.