Salt-related problems in brick masonry and electrokinetic removal of salts

Abstract

When newly plastered masonry facades show dark moist areas at a certain height or the plaster is loose from the masonry, the problem is often linked to increased salt content within the masonry. In the first case, the salts result in hygroscopic moisture and in the latter the salts are precipitating in the interface between the plaster and the masonry resulting in the plaster loosing adhesion. High salt concentrations can further result in salt weathering of masonry where the brick andor mortar areis seriously damaged. There is a lack of proven methods for the removal of salts from masonry. In the present paper, it is shown in laboratory and by a small pilot test that it is possible to remove the salt by applying an electric DC field to the masonry. Very low salt concentrations can be obtained in the laboratory, but the method needs further development before it can be used in actual buildings. The pilot test did show that salts can be removed from real salt contaminated masonry. © 2007 PALGRAVE MACMILLAN LTD.