Two-coat polyaspartic painting system goes the extra mile for ConnDOT

Citation

(2007), "Two-coat polyaspartic painting system goes the extra mile for ConnDOT", Pigment & Resin Technology, Vol. 36 No. 3. https://doi.org/10.1108/prt.2007.12936cad.003

Two-coat polyaspartic painting system goes the extra mile for ConnDOT

Two-coat polyaspartic painting system goes the extra mile for ConnDOT

Reconstruction and rehabilitation of our nation's bridges is a constant concern because of the time and labor involved. Repainting typically involves the application of a three-coat paint system and considerable traffic congestion around the worksite. The Connecticut Department of Transportation recently heard of a proven, high-quality solution that would eliminate many of these problems, and put them on the road to significant cost savings.

Brian Castler, Bureau Chief, Connecticut DOT, Bureau of Finance and Administration, investigated this two- coat paint system for new, and existing steel bridges that have been blast-cleaned to bare metal. The two-coat system is manufactured by The Sherwin-Williams Company using polyaspartic coating technology from Bayer MaterialScience. The primer, Corothane^w I Galvapak, is a VOC-compliant, moisture-curing urethane zinc rich primer, designed for low-temperature application to 208F. The topcoat, Fast Cladw Urethane, is a fast- dry, single coat, polyaspartic specifically formulated for accelerated maintenance painting.

“This is the first two-coat system ever to be placed on NEPCOAT's Qualified Products List,” says Doni Riddle, Vice President, Industrial and Marine Marketing, The Sherwin-Williams Company. “Its performance was judged against that of conventional three-coat systems.”

“There are four primary advantages of polyaspartic coatings technology,” explains Riddle. “It has excellent airless spray characteristics, it applies exceptionally well in humid environments, it can be applied to a specified thickness of 10-14 mils – compared to the 10 to 17 mils dry film thickness of the three-coat system – and it dries exceptionally fast.”

Two-coat system put to the test

Castler liked what he heard. So when the time came to paint Bridge Number 1199 over Interstate 84 in Danbury, Connecticut, he decided to conduct a test. The two spans over I-84 westbound were painted with a traditional three-coat system while the cost-effective, fast- drying, two-coat polyaspartic system was applied to the two eastbound spans. Work on the bridge was conducted during off-peak hours, when there was significantly less traffic.

Paint contractor A. Lagugeni & Son, Inc. of West Haven, CN, agreed to participate in the experiment. The contractor closed one highway lane in each direction during work hours. They then blasted the bridge to SSPC SP-10 “Near White Blast Cleaning.” After blasting, the spans were inspected by both the contractor and the state's quality assurance inspector to ensure proper surface preparation.

When the experiment was complete, the difference was significant. “The Fast Clad topcoat went on like butter,” claims Greg Lagugeni from A. Lagugeni & Son. “It was very user-friendly. The paint went on free of sags and runs, and covered very well. I wouldn't hesitate to use it again.” In addition, the two-coat polyaspartic system resulted in savings of both time and money for ConnDOT.

30 percent faster, 22 percent less expensive

Because they were attempting to determine the advantages and disadvantages of each method, ConnDOT logged and audited every aspect of this project. They compared number of man-hours, cost of traffic control devices, work equipment, and inspection and administrative costs for both systems. Results showed the two- coat technology was approximately 30 percent faster than the traditional system. This meant the road was closed for a shorter period of time, and there was less danger for travelers and the work crew.

Furthermore, the two-coat system resulted in an overall cost savings of approximately 22 percent, while providing the same long-term performance and protection as conventional three-coat systems. In the words of Greg Lagugeni, “The state of Connecticut will get a lot more bridges painted for their budget.”

This new two-coat system was ideal for the I-84 bridge because the highway overpasses were easily accessible from the roadway below with the use of a mobile work platform. The polyaspartic system will no doubt be used on many bridges in the future. According to Suang- Ling Chong of the Federal Highway Administration (FHWA), “This is an attractive coating system for protecting steel bridges since the intermediate layer is eliminated.” Thanks to the new two-coat system, labor and material costs are reduced, and there is less impact on the traveling public.

For more information about Fast Clad DTM Urethane from: The Sherwin-Williams Company, Tel: 1- 800-524-5979; visit the web site: www2.sherwin-williams.com

For more information on Connecticut Department of Transportation: Tel: 1-860-594-2201

For more information about Bayer MaterialScience's polyaspartic coating technology: Tel: 1-800-662- 2927; visit the web site: www.PolyasparticCoatings.com