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The Need for Air Entrainment in High Performance Concrete

File Language:
English


Details

  • Corporate Creators:
    Oklahoma. Department of Transportation. Planning & Research Division
  • Corporate Contributors:
    United States. Department of Transportation. Federal Highway Administration
  • Subject/TRT Terms:
  • Publication/ Report Number:
    FHWA/OK 03(05)
  • Resource Type:
    Tech Report
  • Geographical Coverage:
    United States
  • Edition:
    Final Report
  • Corporate Publisher:
    Oklahoma. Department of Transportation
  • Abstract:
    The use of high performance concrete (HPC) in exterior structures has increased in recent years. Its increased strength and durability make HPC very appealing to the prestressed concrete industry, particularly in bridge girders. Due to its increased strength and durability, HPC can reduce the number of girders, increase bridge spans, decrease bridge depth, and improve bridge durability. Generally, concrete bridges have enjoyed a relatively maintenance free existence. There is some concern that concrete bridge girders should be air entrained; however, the inclusion of air entrainment will reduce concrete strengths. The research program investigated the need for air entrainment in HPC and its effect on HPC bridge girders, an?? the effects of air entrainment on other important properties. Results demonstrated that HPC with water to cementitious materials ratios (w/cm) less than 0.36 demonstrated adequate freeze-thaw resistance. For w/cm greater than 0.36 but less than 0.50, a total air content of 4 percent was adequate to provide freeze thaw resistance. Results also demonstrated expected reductions in concrete strengths when air entrainment was employed. Additionally, testing was performed on HPC girders to determine the effects of large initial compressive stresses and to measure losses. Significant findings include no long term damage with initial prestress compression of 0.70 f'ci. Results also indicated that AASHTO and PCI equations over-estimated prestress losses.
  • Format:
    PDF
  • Funding:
    2145
  • Collection(s):
  • Main Document Checksum:
    urn:sha-512:6b97573227c2a1a446d661f73ea279570cf1ce0e6a9513830377c4bd8ad22a42b3b1b0edbb588ef8491d036e91c27057107fdd8686d9dfb340ee16144666e687
  • Download URL:
  • File Type:
    Filetype[PDF - 7.90 MB ]
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