Electroosmotic permeability in kaolinite and CaCO3 poultice mixtures.

• Electroosmosis in a poultice of kaolinite mixed with tap water has a higher EO flow rate than the poultice with calcium carbonate. • By increasing the concentration of calcium carbonate in the poultice of kaolinite, the EO flow rate decreases. • The EO flow stops when the calcium carbonate concentration increases to 80 % and 20 % of kaolinite in the poultice mixture. • The increase in ionic strength has a negative effect on EO flow. Electrokinetic treatment of masonry for desalination or electroosmotic dewatering depends on a poultice, in which the electrodes are placed, which fulfills several purposes. Poultice composed of kaolinite and CaCO 3 have been shown to have good workability and high pH buffering capacity. In this work, the electroosmotic (EO) permeability is studied in different kaolinite - CaCO 3 mixtures. In addition, the effect on EO of using NaCl as a mixing solution is investigated. A special cell is used to test the EO in the specimens. A phenomenological approach, based on the potential gradient and the flux of solution, was used to calculate the EO flow rate and EO permeability coefficient. Results showed that by increasing the concentration of CaCO 3 in the poultice mixture, the EO flow rate decreased and the poultice with 80 % CaCO 3 and more did not have any EO flow. Furthermore, the ionic strength in the mixing solution decreases the EO flow rate. [ABSTRACT FROM AUTHOR]