Details:

Creators:
Meyers, John J. ; Zheng, Wei ; Washer, Glen
Meyers, John J. ; Zheng, Wei ; Washer, Glen Less -
Corporate Creators:
Missouri University of Science and Technology
Subject/TRT Terms:
[+]
Bridges Bridges--Missouri--Testing Coatings Corrosion Precast Concrete Structural Steel
Publication/ Report Number:
NUTC R233 ; NUTC R238
NUTC R233 ; NUTC R238 Less -
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.


Format:
PDF
Funding:
DTRT06-G-0014
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:c0fecfcd07555075aa42f44aa6a546fcbe954b6d5eb2c6541d0d3d3980b7a140
Download URL:
https://rosap.ntl.bts.gov/view/dot/18352/dot_18352_DS1.pdf
File Type:

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