Validation of a swelling potential index for expansive soils

A new swelling potential index for expansive soils, the Standard Absorption Moisture Content (SAMC), was recommended in Chinese Specifications for Design of Highway Subgrades JTG D30-2004. In order to validate the index, sixteen soils were obtained from six typical areas where expansive soils exist in China. Extensive tests on soil properties indicative of swelling potential, such as Atterberg limits, free swelling ratio, clay content, SAMC, cation exchange capacity, specific surface area and montmorillonite content, were conducted. Correlations between the various indices were obtained and analyzed. The study shows that SAMC is more strongly correlated with the mineralogical and chemical properties, which determine swelling potential in nature, than other physical indices. Therefore, the new swelling potential index was validated to be reliable to identify and classify swelling potential of expansive