InterPore2025

Evaluating Physiochemical Properties of Expansive Soils through Electrokinetic Conditioning

22 May 2025, 09:35

15m

Oral Presentation (MS04) Swelling and shrinking porous media MS04

Speaker

Najibullah Zulfeqar (Auburn University)

Description

This study focuses on the electrokinetic conditioning of expansive soils, emphasizing the physiochemical aspects – an area frequently overlooked in prior research. Expansive soils, known for their propensity to swell and shrink in response to moisture fluctuations, present formidable challenges in geotechnical engineering. These volumetric alterations can lead to soil heave and settlement, jeopardizing the stability of structures built upon them. Electro-kinetic soil conditioning offers a cost-effective, easy-to-implement, and less destructive approach to rapidly stabilize expansive soils under the existing infrastructure, such as pavements and road systems. Ion exchange, chemical transport, and cementation occur near the electrodes during electro-kinetic soil stabilization. Electrokinetic treatment condition was performed on a high plasticity soil, under constant electric field intensities of 67, 100, and 167 V/m, to investigate induced chemical and microstructural changes. A decreasing current was observed during the 7-day conditioning period. Soil pH analysis revealed an acidic region zone near the anode and an alkaline region near the cathode, resulting from water electrolysis reactions. The electric conductivity of the soil increased near the anode while decreasing toward the cathode. X-ray diffraction was unable to distinguish any mineralogical changes in the soil. However, scanning electron microscopy revealed microstructural alterations, including desiccation and void formation near the anode, dense particle aggregation near the cathode, and intermediate changes in between. These findings elucidate the complex processes occurring during electrokinetic soil conditioning, informing optimization strategies by controlling voltage, electrode materials, and treatment time for effective expansive soil stabilization. This finding could offer invaluable insights into its capacity to modify expansive soil properties and mitigate the soil’s swelling and shrinkage propensity.