<p><p><figure id='attachment_2573' style='max-width:878px' class='caption aligncenter'><img class="wp-image-2573 size-full" src="https://www.geoinstitute.org/sites/default/files/geotech-tools-uploads/…; alt="Photographs of electro-kinetic geosynthetics." width="878" height="375" /><figcaption class='caption-text'> Sample pictures of a type of electro-kinetic geosynthetics (EKG) (Courtesy of Electrokinetic, Ltd., (www.electrokinetic.co.uk)</figcaption></figure><h2>Basic Function</h2>Electro-osmosis is the process of movement of pore water in capillaries under the influence of electric potential (direct current).<br><h2>Advantages:</h2><ul> <li>Can be effective in soils with relatively low hydraulic conductivity (silts and clays)</li> <li>Equipment required is not complex and needs minimum surveillance and monitoring</li> <li>No need for heavy construction operation and process as with other chemical or mechanical stabilization methods</li> <li>Depth of stabilization not be a constraint</li></ul><h2>General Description:</h2>Process involves application of direct current (DC) to soils to induce the positive ions (cations) in the pore water to move towards the cathode (-ve) and negative ions (anions) move towards the anode (+ve). Early work in mid 1930s demonstrated that when electric current is applied to certain fine-grained soils, there is an immediate increase in the effective stresses in the soil and thereby increasing the soil shear strength to such a degree that even steep or near vertical cuts remained stable in an otherwise unstable sediment.<br><h2>Geologic Applicability:</h2><ul> <li>Clays and silts with relatively low hydraulic conductivities</li> <li>Can be used to remove contaminants</li></ul><h2>Construction Methods:</h2>Process involves the placement of electrodes in the ground and the development and maintenance of DC potential between the electrodes. Corroded electrodes need frequent replacement and also causes an increase in the resistance at the soil-electrode contacts, thus reducing current density and electrical efficiency. Recently, a more economical alternative with conductive polymers in geosynthetics called as electro-kinetic geosynthetics (EKGs) have been developed which are corrosion resistant and also has the added advantage of facilitating drainage. This new technology is patented. This technology has the potential for using<br>as conductive edge drains for dewatering and stabilization of roadbeds under existing pavements.<br><h2>Additional Information:</h2>Many researchers have applied electro-osmosis on various projects to improve stability of excavations, stabilize foundation soils by lowering the groundwater table, accelerate consolidation, and prevent liquefaction. Some limited studies documented application of electro-osmosis coupled with chemical-osmosis (referred to as electro-kinetic stabilization), wherein the electric current is used to rapidly move the chemical stabilizing agents into clay soils to improve soil properties such as increasing the soil shear strength, reducing the swell potential, increasing the Atterberg limits, etc. The process has the advantage of stabilizing subgrades under existing pavements in addition to stabilizing new subgrades. This particular application has significant potential especially to stabilization of working platforms.<br><h2>SHRP2 Applications:</h2><ul> <li>Embankment and roadway construction over unstable soils</li> <li>Roadway and embankment widening3</li> <li>Stabilization of pavement working platforms</li></ul><h2>Example Successful Applications:</h2><ul> <li>West Branch Dam, Mahoning River, Northeastern Ohio</li></ul><h2>Alternate Technologies:</h2>Prefabricated vertical drains, vacuum consolidation, various grouting methods, soil mixing, jet grouting.<br><h2>Potential Disadvantages:</h2><ul> <li>Lack of detailed case history data demonstrating the cost benefits in comparison with other conventionally used methods of soil improvement,</li> <li>Lack of specifications or guidelines on use of appropriate design, QC/QA, and construction methods specific to different applications</li></ul><h2>Key References for this Fact Sheet:</h2>Acar Y. B. (1992). “Electrokinetic soil processing: A review of the state-of- the-art,” <em>Grouting, Soil Improvement, and Geosynthetics,</em> Geotechnical Special Publication No. 30, Vol. 2, ASCE, New York, 1420–1432.</p><p>Casagrande, L. (1983). “Stabilization of soils by means of electro-osmosis – State-of¬-the-art,” Boston Society of Civil Engineers Section, ASCE, Vol. 69, No. 2, 255–302.</p><p>Mitchell, J.K., and Soga, K (2005).<em> Fundamentals of Soil Behavior</em>, 3rd Edition, John Wiley &amp; Sons, Inc., New Jersey, pp. 291-305.</p><p>&nbsp;</p></p>