Investigating causes and determine repair needs to mitigate falling concrete from bridge decks.

Details

• Creators:
  Grace, Nabil ; Jensen, Elin
• Corporate Creators:
  Lawrence Technological University
• Subject/TRT Terms:
  • Bridge decks
  • Concrete bridges
  • Corrosion
  • Nondestructive tests
  • Field tests
  • Laboratory tests
  • Spalling
  • Freeze thaw tests
  • Concrete bridges--Floors--Corrosion
  • Concrete bridges--Cracking
• Publication/ Report Number:
  RC-1567
• Resource Type:
  Tech Report
• Geographical Coverage:
  Michigan
• Corporate Publisher:
  Michigan. Dept. of Transportation. Office of Research and Best Practices
• Abstract:
  This study developed a procedure to identify concrete bridge decks that are exhibiting the characteristics associated ; with falling concrete. Field exploratory work on reinforced concrete bridge decks was supported by analytical and ; laboratory investigations. The field work included visual inspection, non-destructive tests, and sampling of full-depth ; cores and powder samples from the bottom of the bridge deck. Chief variables assessed were the chance of corrosion ; by the half-cell potential, chloride content at the location of the bottom reinforcement, and the concrete pH level. The ; chloride diffusivity was estimated from the chloride profile. The laboratory investigation was performed on bridge ; deck beams. The beams were constructed from concrete containing chloride levels known to cause corrosion as well as ; from a control concrete. Beams were subjected to freeze-thaw or saltwater followed by repeated loading to simulate ; field conditions. The following characteristics were quantified: chance of corrosion, corrosion rate, chloride content, ; flexural response as a function of environmental exposure and repeated loads, and ultimate strength. The size of the ; porous zone around the reinforcement was determined using an environmental scanning electron microscope. Finally, a ; strategy was developed to assess if a bridge deck exhibited the characteristics associated with falling concrete. The ; strategy included visual inspection of cracking and spalling, assessment of chance of corrosion, chloride content, and ; pH levels. If any of these measures exceed critical levels a service life calculation needs to be performed. Based on ; existing mathematical models, the time to corrosion initiation and time to corrosion cracking can be predicted. The ; resulting time is then compared to the age of the bridge. From this information proper planning for future repair needs ; can be made.
  More +
• Format:
  PDF
• Funding:
  108621
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/25379/dot_25379_DS1.pdf
• File Type:
  [PDF - 4.42 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:6dfcaf596c88bc81a414b35472533b77d5f93f15b8d7048b76526c014d25f2e5aaa741a277d0d1eb09064c03bba2ba895b9c9249751d1b2f777a21032703b475