Infrastructure Maintenance and Repair
Steel bridges, concrete bridges, highway sign structures, bridge expansion joints and even gates in lock and dam facilities all have a history of receiving metalized corrosion protective coatings.
Metalizing offers a strong defense against corrosion on all of these types of structures.
STEEL BRIDGES
Steel Bridges
Metalizing offers long term corrosion protection for steel bridges. The ability of thermal sprayed zinc, aluminum, and zinc/aluminum coatings to provide effective long term protection for steel exposed to a variety of environments is well proven.
Projected over a 50 year period, it has been estimated that metalizing steel bridges could reduce coating costs by 50%.
The Rainbow Bridge, connecting Niagara Falls New York, USA to Niagara Falls, Ontario, Canada, was metalized with 8-12 mils of 85/15 zinc/aluminum. A properly applied metalized coating can realistically provide 30 years of corrosion protection.
Coating thickness can be varied depending on the atmospheric condition at the installation site. Where required, a thicker coating can be applied to extend the service life of the coating.
CONCRETE BRIDGES
Concrete Bridges
Corrosion of reinforcing steel in concrete structures has been a growing concern for many years. The corrosion process can be slowed or eliminated by controlling the galvanic current that is generated within the concrete when the rebar rusts. This current reversal is called cathodic protection.
The application of the zinc metalized coating to steel reinforced concrete is done to protect the rebar from corrosion. In an impressed current cathodic protection (ICCP) system the zinc metalized coating is an anode and must be electrically isolated from the rebar.
The Oregon DOT has specified zinc metalizing for coastal bridges since 1985. Over 1,000,000 square feet of metalizing has been accomplished to provide a conductive coating anode protecting the bridges along the Oregon Coast.
The Cape Creek Bridge in Oregon was the first complete structure to use zinc metallizing in a cathodic protection application. Zinc was applied to concrete on the eastbound portion of the Howard Franklin Bridge, which spans over two miles of Tampa Bay, Florida. Over 120,000 square feet of concrete was metalized in this Florida Department of Transportation rehabilitation project.
LOCK AND DAM FACILITIES
Lock and Dam Facilities
Metalized coatings have been used to address corrosion related maintenance problems encountered in lock and dam facilities. Some facilities have used metalized coatings for everything from gates to handrails.
Metalized 85/15 zinc/aluminum coatings offer a positive alternative to conventional paint coatings for use in abrasion-corrosion environments found in many river dam facilities.