Structural steel coatings for corrosion mitigation.

Details

• Creators:
  Meyers, John J. ; Zheng, Wei ; Washer, Glen
• Corporate Creators:
  Missouri University of Science and Technology
• Subject/TRT Terms:
  • Precast concrete
  • Bridges
  • Structural steel
  • Coatings
  • Corrosion
  • Precast concrete
  • Bridges--Missouri--Testing
• Publication/ Report Number:
  NUTC R233 ; NUTC R238
• Resource Type:
  Tech Report
• Geographical Coverage:
  Missouri
• Edition:
  Final report.
• Corporate Publisher:
  Missouri University of Science and Technology
• Abstract:
  Task 1 of this project was to survey the performance of coating systems for steel bridges in Missouri and to evaluate coating and ; recoating practices. Task 1 was led under the direction of Dr. Glenn Washer from the University of Missouri located in Columbia, ; MO. A specific literature review focused on current state-of-the-practice for overcoatings, bridge coating assessment and rating, ; deterioration rate modeling as well as the risk assessment for overcoating. A new coating evaluation guideline was created to meet the ; needs of bridge maintenance in Missouri. Finally a field survey was carried out onto the existing bridge coatings across 10 Missouri ; Department of Transportation (MoDOT) districts and 26 counties. It was found that system S and G perform very well in many of the ; situations observed. The survey indicated that in many cases system S overcoatings are providing service life extension for the coating ; system, with some early failures resulting from severe exposure to deck drainage and corrosion. Deck condition, drainage, and joint ; conditions were found to be the dominate factor in deterioration of the coating system, regardless of the age of the coating. Task 2 of ; this project investigated the performance of new types of coating technologies on bridge corrosion mitigation and was led under the ; direction of Dr. John Myers from the Missouri University of Science and Technology located in Rolla, MO. Twelve coating systems ; including MoDOT system G were evaluated through several laboratory tests to study and predict the field performance and durability ; of new coating technologies. The new coating systems investigated in this study involved polyurea, polyaspartic polyurea, ; polysiloxane polymers and fluoropolymer. To date, these coating system technologies have not been used as a steel structural coatings ; system in the State of Missouri by MoDOT. The laboratory tests consist of freeze-thaw stability, salt fog resistance, QUV weathering ; and electrochemical tests. The comparison study was carried out to benchmark and understand the pros and cons of these new coating ; systems. In addition, two coating systems served as overcoating studies for lead-based paint systems representative of older existing ; bridges in the state of Missouri. These overcoating systems were evaluated using an accelerated lab test method and electrochemical ; test. The performance of the existing MoDOT calcium sulfonate (CSA) overcoating system (system S) was also studied within the test ; matrix for comparative purposes. The test results show that moisture cured urethane micaceous iron oxide zinc/polyurea polyasp ; is a promising coating system for recoating of new steel ; artic ; bridges and that aliphatic polyaspartic polyurea can also be applied on ; existing coatings after the surface is properly prepared.
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• Format:
  PDF
• Funding:
  DTRT06-G-0014
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/18352/dot_18352_DS1.pdf
• File Type:
  [PDF - 74.22 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:c0fecfcd07555075aa42f44aa6a546fcbe954b6d5eb2c6541d0d3d3980b7a140