Comparison of the shrinkage limit values obtained from the mercury displacement, water displacement, and water submersion methods

In this study, detailed experiments were carried out to clarify some physical properties and behavior of paraffin that may affect the shrinkage limit of soils. Then the shrinkage limit values of 22 different natural soil samples were determined by both conventional mercury displacement and water displacement, and water submersion methods. Shrinkage limit values obtained by different methods were correlated using linear regression analyses. The experiments were generally carried out according to the procedures described in relevant standards except for some procedural modifications. As a result of the experiments, it was determined that (1) the shrinkage limit values of soils are highly sensitive to the paraffin density, (2) the optimum range of paraffin temperature is between about 70 and 57 °C for a proper coating of the soil pat, and (3) hygroscopic dry mass of the soil pat should be used for determining the coating mass. Besides, it was revealed that the shrinkage limit values obtained from the paraffin coating methods were in good agreement with those from the conventional mercury displacement method, provided that potential sources of error in paraffin coating methods are correctly identified and eliminated.