Long-term post-tensioned beam exposure test specimens : final evaluation.

Details

• Creators:
  Salas, Reuben M. ; Kotys, A. L. ; West, J. S. ; Schokker, Andrea J. ; Breen, John E. ; Kreger, Michael E.
• Corporate Creators:
  University of Texas at Austin. Center for Transportation Research
• Corporate Contributors:
  Texas. Dept. of Transportation. Research and Technology Implementation Office ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Posttensioning
  • High performance concrete
  • Beams
  • corrosion
  • grout
  • post-tensioned concrete tendons
  • post-tensioning ducts
  • mixed reinforcement
  • duct splicer
  • concrete cracking
  More +
• Publication/ Report Number:
  FHWA/TX-04/0-1405-7
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas
• Corporate Publisher:
  Texas Department of Transportation. Research and Technology Implementation Office
• Abstract:
  In the last few years, the effectiveness of cement grout in galvanized or polyethylene ducts, the most widely used corrosion protection system for ; multistrand bonded post-tensioned concrete tendons, has been under debate, due to significant tendon corrosion damage, several reported failures ; of individual tendons as well as a few collapses of non-typical structures. While experience in the USA has been generally good, some foreign ; experience has been less than satisfactory. ; This report is part of a comprehensive research program started in 1993, which has the objectives to examine the use of post-tensioning in bridge ; substructures, identify durability concerns and existing technology, develop and carry out an experimental testing program, and conclude with ; durability design guidelines. ; Three experimental programs were developed: A long term macrocell corrosion test series, to investigate corrosion protection for internal ; tendons in precast segmental construction; a long term beam corrosion test series, to examine the effects of post-tensioning on corrosion ; protection as affected by crack width; and, a long term column corrosion test series, to examine corrosion protection in vertical elements. ; Preliminary design guidelines were developed previously in the overall study by the initial researchers, after an extensive literature review. ; This report documents the final evaluation of the long-term post-tensioned beam exposure test specimens, after comprehensive autopsies ; of selected beams and updating the durability design guidelines based on the exposure testing and autopsy results. ; After autopsies were performed, overall findings indicate negative durability effects due to the use of mixed reinforcement, galvanized ; steel ducts, and industry standard or heat-shrink galvanized duct splices. The width of cracks was shown to have a direct negative effect ; on specimen performance. Grout voids were found to be detrimental to the durability of both galvanized ducts and strand. On the other ; hand, very positive effects were found with the use of high performance concrete, high post-tensioning levels, and plastic ducts.
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• Format:
  PDF
• Funding:
  Research Study 0-1405
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31644/dot_31644_DS1.pdf
• File Type:
  [PDF - 7.03 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:bb95c224eea8936aeb848024a328faf95102e699e740bf9a04cd82de43367ab1