Laboratory investigation of concrete beam-end treatments.

Details

• Creators:
  Hosteng, Travis ; Abu-Hawash, Ahmad ; Port, Gordon ; Phares, Brent
• Corporate Creators:
  Iowa State University. Bridge Engineering Center
• Corporate Contributors:
  Iowa. Dept. of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Beams
  • Prestressed concrete bridges
  • Expansion joints
  • Anticorrosion coatings
  • Laboratory tests
  • Bridge design
• 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.
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• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29070/dot_29070_DS1.pdf
• File Type:
  [PDF - 7.92 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:08cd918fefc0ef574edc95aaa87fae5d25f76b93b5870e43baaf59b43e2a0613d7843fd996d7c6af7e24db61e2da24849e6bd5b7ac67b822c7f60c047d07f293