Chloride Concentration and Blow-through Analyses for Concrete Bridge Deck Rehabilitation Using Hydrodemolition

Details

• Creators:
  Guthrie, W Spencer ; Roper, Elizabeth A
• Corporate Creators:
  Brigham Young University. Department of Civil and Environmental Engineering
• Corporate Contributors:
  Utah Department of Transportation ; United States. Department of Transportation. Federal Highway Administration
• Subject/TRT Terms:
  Atmospheric Diffusion Blow-through Bridge Decks Chloride Concentration Chlorides Concentration (Chemistry) Concrete Bridges Hydrodemolition Rehabilitation (Maintenance) Surface Treating
• Publication/ Report Number:
  UT-20.27
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States ; Utah
• Edition:
  Final, March 2016 to May 2018
• Corporate Publisher:
  Utah Department of Transportation
• Abstract:
  The objectives of this research were 1) to investigate the effects of hydrodemolition treatment timing on chloride concentration profiles in concrete bridge decks for depths of concrete removal below the top mat of reinforcing steel and 2) to investigate factors that influence the occurrence of blow-throughs in concrete bridge decks when hydrodemolition is used. The scope of this research included a questionnaire survey of hydrodemolition companies to summarize common practices in the field, numerical modeling of chloride concentration to investigate hydrodemolition treatment timing on typical Utah bridge decks, and structural analysis to investigate factors that influence the occurrence of blow-throughs during hydrodemolition. The survey responses are valuable for understanding typical practices and were used to design the numerical experiments. The results of numerical modeling indicate that, when a surface treatment is used, the chloride concentration at either the top or bottom mat of reinforcing steel does not reach or exceed 2.0 lb of chloride per cubic yard of concrete after rehabilitation during the 75 years of simulated bridge deck service life. The results also indicate that, when a surface treatment is not used, the chloride concentration at the top mat of reinforcement exceeds 2.0 lb of chloride per cubic yard of concrete within 10, 15, and 20 years after rehabilitation for original cover depth values of 2.0, 2.5, and 3.0 in., respectively. The results of structural analysis indicate that the factor of safety against blow-throughs significantly increases with increasing values of transverse rebar spacing and concrete compressive strength and decreasing values of depth of removal below the bottom of the top reinforcing mat, orifice size, and water pressure within the investigated ranges of these parameters.
• Format:
  PDF
• Funding:
  15-8775
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:1ae856b497e324d90842cdfda65223a8837b99ccfe247babe409ee38a0a3d928
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/58687/dot_58687_DS1.pdf
• File Type:
  [PDF - 3.16 MB ]