Soil-Water Characteristic Curves for Clayey Soil Treated with Cement or Lime

Geotechnical experts have been able to characterize the suction behavior of unsaturated soil through the development of soil-water characteristic curves (SWCCs), which can in turn be used to solve various geotechnical engineering problems related to slope stability, bearing capacity of foundations, seepage, etc. Although considerable progress in the field of unsaturated soil mechanics has been achieved, the suction behavior of cementitiously stabilized soil, which is commonly used in a variety of ground improvement projects, is still not well understood. The objective of this research was to determine the effects of cement and lime stabilization on the SWCC of a clayey subgrade soil sampled from Monticello, Utah. The scope of work included extensive laboratory testing and data analyses. Six samples each of untreated, lime-treated, and cement-treated material were compacted, for a total of 18 samples. SWCC testing was accomplished using filter papers. Stabilization with cement slightly increased the air-entry potential, while stabilization with lime decreased the air-entry potential. However, stabilization with cement or lime consistently increased the pore-size distribution index, indicating a finer soil matrix that would be expected to drain water more slowly and therefore also experience less fluctuation in water content than the untreated soil.