Details:

Creators:
Hosteng, Travis ; Abu-Hawash, Ahmad ; Port, Gordon ; Phares, Brent
Hosteng, Travis ; Abu-Hawash, Ahmad ; Port, Gordon ; Phares, Brent Less -
Corporate Creators:
Iowa State University. Bridge Engineering Center
Corporate Contributors:
Iowa. Dept. of Transportation ; United States. Federal Highway Administration
Iowa. Dept. of Transportation ; United States. Federal Highway Administration Less -
Subject/TRT Terms:
[+]
Anticorrosion Coatings Beams Bridge Design Expansion Joints Laboratory Tests Prestressed Concrete Bridges
Publication/ Report Number:
InTrans Project 12-442
Resource Type:
Tech Report
Geographical Coverage:
Iowa
Corporate Publisher:
Iowa State University. Institute for Transportation
Abstract:
The ends of prestressed concrete beams under expansion joints are often exposed to moisture and chlorides. Left unprotected, the

moisture and chlorides come in contact with the ends of the prestressing strands and/or the mild reinforcing, resulting in

corrosion. Once deterioration begins, it progresses unless some process is employed to address it. Deterioration can lead to loss of

bearing area and therefore a reduction in bridge capacity.

Previous research has looked into the use of concrete coatings (silanes, epoxies, fiber-reinforced polymers, etc.) for protecting

prestressed concrete beam ends but found that little to no laboratory research has been done related to the performance of these

coatings in this specific type of application.

The Iowa Department of Transportation (DOT) currently specifies coating the ends of exposed prestressed concrete beams with

Sikagard 62 (a high-build, protective, solvent-free, epoxy coating) at the precast plant prior to installation on the bridge.

However, no physical testing of Sikagard 62 in this application has been completed. In addition, the Iowa DOT continues to see

deterioration in the prestressed concrete beam ends, even those treated with Sikagard 62.

The goals of this project were to evaluate the performance of the Iowa DOT-specified beam-end coating as well as other concrete

coating alternatives based on the American Association of State Highway and Transportation Officials (AASHTO) T259-80

chloride ion penetration test and to test their performance on in-service bridges throughout the duration of the project. In addition,

alternative beam-end forming details were developed and evaluated for their potential to mitigate and/or eliminate the

deterioration caused by corrosion of the prestressing strands on prestressed concrete beam ends used in bridges with expansion

joints. The alternative beam-end details consisted of individual strand blockouts, an individual blockout for a cluster of strands,

dual blockouts for two clusters of strands, and drilling out the strands after they are flush cut. The goal of all of the forming

alternatives was to offset the ends of the prestressing strands from the end face of the beam and then cover them with a

grout/concrete layer, thereby limiting or eliminating their exposure to moisture and chlorides.


Format:
PDF
Collection(s):
US Transportation Collection
Main Document Checksum:
[+]
urn:sha256:568144e5487fa7ac6cc5ea5f174effacc42ebd08476ab2d675831a33138e6dc1
Download URL:
https://rosap.ntl.bts.gov/view/dot/29070/dot_29070_DS1.pdf
File Type:

Supporting Files

• No Additional Files

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