Electro-Osmotic Pulse Technology for Civil Works

By Dana Finney

A technology proven effective in drying up wet basements is now being evaluated for use in civil works concrete structures to control water seepage. Electro-Osmotic Pulse (EOP) technology forces moisture to flow through concrete surfaces against the hydraulic gradient when an electric field is applied to an embedded anode system. This flow is initiated by the movement of cations (positively charged ions) present in a porous medium such as concrete toward the negative earth. Water surrounding the cations moves with them.

The Corps of Engineers owns and maintains many buried and immersed concrete structures that are subject to seepage, cracking, and spalling, such as locks, dams, and hydroelectric plants. These conditions account for more than 75 percent of concrete deficiencies reported in the Corps Periodic Inspection Program. Cracking alone accounts for almost 40 percent of the total deficiencies. In addition, cracks allow moisture intrusion and subsequent freeze-thaw cycles cause raveling of the cracks. The concrete becomes saturated, leading to deterioration and loss of structural integrity.

ERDC's Construction Engineering Research Laboratory (CERL) has worked with industry partners APS Materials and Drytronic, Inc., to develop EOP into a viable technology. Current research into using EOP for civil works structures addresses the following issues: (1) electro-osmotic pressure required to balance hydrostatic pressure (head); (2) how concrete characteristics influence operation; (3) how soil and water conditions influence operation; (4) how EOP pulse characteristics influence operation; (5) how cracks and voids in the concrete influence operation; and (6) overall effectiveness of EOP technology in control of water seepage. The research includes both laboratory and field testing.

EOP technology offers substantial benefits over conventional methods of controlling water seepage in concrete structures: (1) significant reduction in installation cost, installation time, and disruptions to operation; (2) low operational costs; (3) reduction in maintenance of equipment and structure; (4) significant improvement in interior air quality by reducing the relative humidity for 95 % to 70 %; and (5) elimination of freeze/thaw cycles and subsequent crack development.

For more information, please contact Vincent Hock at ERDC-CERL, (217) 373-6753, email: Vincent.F.Hock@erdc.usace.army.mil.