Optimizing electrokinetic clay soil improvement using calcium dioxide solutions: a comprehensive approach

Improvement of low permeability soils with a high plasticity index cannot be done by compaction or consolidation. The structure of clay is influenced by the history of soil formation. Clay is composed of two tetrahedrals with one octahedral. Van der Waals bonds bind both. Montmorillonite has the weakest bonds so other minerals easily enter and bond within its structure. The ability of clay soils to absorb water or other approaching minerals is due to their cation exchange capacity (CEC). Clay with its negative ions will attract positive ions that approach the clay surface. Water with H+ content will easily enter the structure of the clay soil, be bound in it, and cause the soil to swell. Swelling causes the soil to have low physical and mechanical properties, so the bearing capacity of the soil is linearly low. The distribution of clay soils in Indonesia and the prevailing climatic conditions make it difficult for geotechnical engineers to carry out soil improvement in situ. Electrokinetic soil improvement is effective on clay soils. With the nature and characteristics of clay soil, a stabilizing ion with a positive charge is required. Positive ions will enter due to the CEC process and affect the mineral content of the soil thereby improving the physical and mechanical properties of the clay soil. Because of this, it is necessary to conduct this research to optimize the stabilization of clay soil using the electrokinetic method with calcium dioxide solution. The variation of applied voltage gives different results on the change of soil mechanical properties. Electrokinetic stabilized soil reached the maximum value in the shear strength of SE4 soil, which is 0.128 kg/cm2 or increased by 200 %. Shrinkage expansion decreased by 50 % from natural soil of 5.8 % to 2.14 %.