An Investigation Into The Use Of Lime-Stabilized Clay As Subgrade Material

This study involves the collection of clay sample at a site along Ise / Ikere Road at Ikere-Ekiti region and evaluation of its properties in natural state and after stabilization with lime. The major objective of the study is to determine the optimum lime content that will stabilize the clay soil adequately. Also, it investigates the level of improvement that could be achieved by stabilizing clayey soil with lime. The tests carried out include mechanical sieve analysis and hydrometer test, specific gravity, moisture content, Atterberg limit test, compaction test, and California bearing ratio test. The high moisture content of the natual clay soil clearly shows its high water absorption capability. The addition of lime reduces the plasticity index at 8% and 10% lime content. The maximum dry density (MDD) increases with an increase in lime content from 0 to 8%, while a reduction in the MDD was observed at 10%. The maximum optimum moisture content (OMC) was recorded at 10% lime content. The California bearing ratio (CBR) of the lime stabilized clay increases for lime content of 2% to 8%, with the maximum value obtained at 8%, while a reduction in the CBR was observed at 10%. The reduction in the CBR at 10% might be due to the excess lime in the clay not required for the early strength gain as a result of flocculation. The need for soil stabilization may arise, if the natural soil to be built on in an area is of poor engineering properties or when a section of the land is found not suitable to support the foundation in its natural state. In some cases, for instance in road pavement construction, the stabilization of layers of the pavement like the subgrade, subbase and the base may be carried out as a way of reducing the cost of construction, which is achieved by improving the load carrying capacity of these layers and consequently reducing the thickness of the surfacing layer (asphalt concrete or cement concrete, which is the most expensive). The problem associated with clay soil is due to high swelling (caused by its high water absoption capability) and shrinkage of the soil, compaction difficulty and high plasticity of the soil. The properties of soil-lime mixtures are