Effect of ionic solutions on the performance of electrokinetic treatment of soft soils

Abstract

This study evaluates the performance of electrokinetic (EK) treatment to improve the engineering properties of soft soils. Laboratory tests were conducted using ionic solutions of calcium chloride, CaCl2 and sodium carbonate, Na2CO3. Atterberg limits, unconfined compression, electrochemical, thermal, and microscopic tests were performed in terms of treatment duration, anode-to-cathode distances, and different combinations of ionic solutions as calcium chloride-distilled water (CaCl2-DW), sodium carbonate-distilled water (Na2CO3-DW) and calcium chloride-sodium carbonate (CaCl2-Na2CO3). EK treatment caused a reduction in the specific surface area, S-a, cation exchange capacity, CEC, and plasticity resulting in 26%, 14%, 19% reduction using CaCl2-DW, Na2CO3-DW, and CaCl2-Na2CO3 ionic solutions, respectively. The formation of the new compounds, calcium aluminosilicate hydrates, CASH resulted in the strength gain of the EK treated soils and increased the strength from 21 kPa to 90 kPa, 63 kPa, and 92 kPa with the ionic solutions of CaCl2-DW, Na2CO3-DW, and CaCl2-Na2CO3, respectively.