Electro-osmotic and hydraulic flow rates through kaolinite and bentonite clays

The objective of this paper is to discuss the effects of electrokinetics on the rate of flow of water through some low penneable clay soils. Experiments were carried out on test specimens prepared by compacting commerciully available kaolinite and sodium bentonite clays. Using falling head penneability tests, hydraulic conductivity values of these clay soils were determined. Subsequently, the experiments were repeated under different electric gradients to assess the effects of electrokinetics on the rate of flow. The flow characteristics were evaluated using the rate of electrooslllotic flow of water Q, (em'/s), coefficient of electroosmotic penneability k, (cm'lY/s), coetlicient of water transport etliciency k; (cm'/Amp/s). The test results suggest that the rate of flow of water through low penneable clay soils is significantly increased by some orders of magnitude due to the application of a direct current. This flow increase appears to be more pronounced for clays that have lower hydraulic conductivity values. It is noticed that electroosl1lotic penneability is independent ofclay type while the voltage gradienl has minimal effect on electroosmotic rate of flow for the tested clay soils.C