Laboratory and Test-Site Testing of Moisture-Cured Urethanes on Steel in Salt-Rich Environment

Chong, Shuang-Ling; Yao, Yuan

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Laboratory and Test-Site Testing of Moisture-Cured Urethanes on Steel in Salt-Rich Environment

2000-12-01
By Chong, Shuang-Ling ; Yao, Yuan

File Language:

English

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Creators:

Chong, Shuang-Ling ; Yao, Yuan
Corporate Creators:

United States. Department of Transportation. Federal Highway Administration. Office of Infrastructure Research and Development
Subject/TRT Terms:
Publication/ Report Number:

FHWA-RD-00-156
Resource Type:

Tech Report
Geographical Coverage:

United States
Corporate Publisher:

United States. Federal Highway Administration
Description:

Three 3-coat moisture-cured (MC) urethane commercial products formulated for protecting new steel (SSPC-SP 10) and power tool-cleaned steel (SSPC-SP 3) surfaces against corrosion were evaluated; the total coating film thickness was about 75 microns. Zinc-rich MC-urethane primers were used for SSPC-SP 10 steel surfaces whereas the primers for SSPC-SP 3 surfaces contained zero or a small amount of zinc; the same midcoats and topcoats were used for both steel surfaces. A chloride concentration of 20 micrograms per sq cm on the steel surfaces was found to be significant to reduce the coating performance at the scribe of SSPC-SP 10 steel surfaces; however, the chloride effect was found to be minimal for SSPC-SP 3 steel surfaces. Interestingly, all the scribe creepages increased linearly with the laboratory test time up to 4,000 h. Furthermore, the addition of a sealer to the primer/midcoat/topcoat systems unexpectedly impaired the performance at the scribe on SSPC-SP 3 steel surfaces when compared with those systems without a sealer. On the other hand, a coating system with sealer/primer/topcoat without a midcoat developed severe underfilm corrosion probably due to insufficient film thickness.
Format:

PDF
Download URL:

https://rosap.ntl.bts.gov/view/dot/14703/dot_14703_DS1.pdf
File Type:

[PDF - 9.28 MB]
Collection(s):

US Transportation Collection ; Federal Highway Administration
Main Document Checksum:

urn:sha-512:b5a856d9749b5651530939e8c835c5a90b7ea55f17db1c60547dbb6ca290e5460c192d7b4c9daef3a5401048260715e605e477100e8f35e2235686e44d66447c

File Language:

English

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