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:
  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:sha-512:08cd918fefc0ef574edc95aaa87fae5d25f76b93b5870e43baaf59b43e2a0613d7843fd996d7c6af7e24db61e2da24849e6bd5b7ac67b822c7f60c047d07f293
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/29070/dot_29070_DS1.pdf
• File Type:
  [PDF - 7.92 MB ]