Since 1985, the Connecticut Department of Transportation has used cathodic protection (CP) as a rehabilitation method to extend the service life of corroding concrete bridge decks. The first installation made use of a conductive polymer grout installed in slots on a bridge near Middlefield. This system continues to provide corrosion protection to the reinforcing steel.

More recently, the ELGARD™ CP system has been used on a variety of bridge rehabilitation projects in Connecticut. The system consists of a titanium mesh, which is typically installed beneath a concrete overlay, such as latex modified concrete. The benefit of this system is that the mesh will slowly oxidize in favor of the reinforcing steel and provide long life to the structure (ie. > 20 years).

Several criteria are used to determine if a structure is a good candidate for CP. These include: remaining life, percent delamination, condition of the structure, and availability of AC power. Connecticut will consider CP under the following conditions:

A 20-year added service life is required.

The chloride content around the top mat is high (>1.0 lb. / cu. yd.).

The deck is structurally sound and the compressive strength exceeds 3,000 psi.

The bottom slab does not show extensive areas of cracking.

The deck is bare and the superstructure cannot carry additional dead load by an asphalt overlay.

Corrosion of embedded rebar on bridge decks is primarily caused by the ingress of salt into the concrete. The expansive forces created by the rust leads to cracking, delamination and spalling of the concrete. CP arrests corrosion in bridge decks by eliminating the corroding areas on the rebar and making the steel more passive.

Corrpro, the worldwide licensee of the ELGARD™ system for cathodic protection of reinforced concrete structures, provides CP system design, materials, installation, testing and supervision.

Project Data:

Owner:	Connecticut Department of Transportation
Client Contact:	Mr. Eric Lohrey telephone: (860) 258-0303
Anode Type:	ELGARD™ 210 & 300 Anode Mesh
Installation Date / Location:	1989 - Rt. 229 o/I-84, Southington 1992 - Rt. 8 NB, Thomaston 1990 - Rt. 508 EB Ramp, Farmington 1993 - US 7 SB, Danbury 1992 - Rt. 8, Naugatuck 1993 - Rt. I-395, Norwich 1992 - College St. o/Rt. 34, New Haven 1993 - US 7, Norwalk 1992 - Rt. I-395, Norwich 1993 - US 8 NB, Thomaston

Leading governmental and independent trade organizations have monitored, tested, and reported on corrosion control strategies over the past three decades. These groups include the American Concrete Institute, National Association of Corrosion Engineers, and Federal Highway Administration. They advocate CP as the only rehabilitation technique that effectively stops corrosion in salt-contaminated structures, regardless of the chloride content of the concrete.

ELGARD™ is a trademark of Eltech Systems Corporation.