This study presents and analyzes the results of a series of Atterberg's limit tests, Proctor compaction tests, California bearing ratio tests and Unconfined Compressive Strength tests performed on Black cotton soil treated with mixture of various Lime and RBI Grade 81 contents and compacted under the optimum Proctor conditions. These test results show that the geotechnical parameters values are concordant and confirm the bearing capacity improvement of this natural clay, which is translated by a significant increase in soil strength.