Island Mapping of Chloride Deposition Rate

Corrosion of reinforcing steel in concrete is a major concern for all reinforced and prestressed concrete structures in coastal environments. Of the 580,000 bridges in the U.S.A., 160,000 are structurally deficient. Many of these deficiencies stem from the damage caused by excessive corrosion of reinforcing steel causing concrete spalling. The major initiator of corrosion of reinforcing steel is the ingress of chlorides through the cover concrete. In coastal environments such as Hawaii, chlorides accumulate on the surface of concrete structures through direct contact with seawater, splash zone exposure, or airborne salts for near-coastal environments. The Bridge Section of the Hawaii Department of Transportation is utilizing Pontis, an AASHTO bridge management system, to manage the State bridge inventory. In order to predict the likely onset of corrosion in both existing and new bridges, the Bridge Section is utilizing a recently developed LIFE 365 Corrosion Prediction model. LIFE 365 considers numerous variables, including the concrete material properties, use of admixtures and reinforcement coating, concrete cover thickness, and environmental and exposure conditions. The most important environmental conditions are the ambient temperature (relatively constant and well defined in Hawaii) and the Surface-Chloride-Concentration Profile, which indicates the rate at which chlorides accumulate on the surface of the concrete. No information is currently available regarding the rate of chloride accumulation at various locations in Hawaii. This variable has a significant effect on the time to onset of corrosion and will greatly affect the output from the LIFE 365 computer model. Inaccurate predictions can lead to expensive mismanagement of the transportation infrastructure. If onset of corrosion can be predicted more accurately, relatively inexpensive remedial measures can be implemented so as to avoid more expensive repairs once cracking and spalling occur. The objective of the proposed research is to develop chloride-deposition-rate maps for the Hawaiian Islands. Chloride deposition rates will be monitored at representative locations around Oahu and inferences will be made regarding the deposition rates for similar locations on the neighbor islands.

    Language

    • English

    Project

    • Status: Active
    • Funding: $99000.00
    • Contract Numbers:

      53634

      HWY-L-2005-02

    • Sponsor Organizations:

      Federal Highway Administration

      300 Ala Moana Boulevard
      Honolulu, HI  United States  96850

      Hawaii Department of Transportation

      869 Punchbowl Street
      Honolulu, HI  United States  96813-5097
    • Project Managers:

      Santo, Paul

    • Performing Organizations:

      University of Hawaii, Manoa

      College of Engineering, Department of Civil and Environmental Engineering
      2540 Dole Street, Holmes Hall 383
      Honolulu, HI  United States  96822
    • Principal Investigators:

      Robertson, Ian

    • Start Date: 20050801
    • Expected Completion Date: 0
    • Actual Completion Date: 20070131
    • Source Data: RiP Project 12810

    Subject/Index Terms

    Filing Info

    • Accession Number: 01460457
    • Record Type: Research project
    • Source Agency: Hawaii Department of Transportation
    • Contract Numbers: 53634, HWY-L-2005-02
    • Files: RiP, USDOT, STATEDOT
    • Created Date: Jan 3 2013 1:25PM