STP1215: Petrographic Examination of Reinforced Concrete from Cathodically Protected Structures

    Lankard, DR
    President and Research Technician, Lankard Materials Laboratory, Columbus, OH

    Scaglione, NJ
    President and Research Technician, Lankard Materials Laboratory, Columbus, OH

    Bennett, JE
    Research Fellow, ELTECH Research Corporation, Fairborn Harbor, OH

    Pages: 23    Published: Jan 1994


    Abstract

    Core samples were obtained from eleven 18-year to 32-year old reinforced concrete bridge and parking structures that have been under cathodic protection for 2 to 10 years. Characterization studies were conducted on the cores to assess the effects of the sustained cathodic protection current on the anode, the anode/concrete component, and the cathode/concrete component of the cathodic protection system. Characterization techniques included (1) conventional optical petrographie techniques, (2) SEM/EDS techniques, and (3) chloride ion content measurements. The 11 structures represent 8 different CP systems.

    Data are also presented on cores taken from 3 ft. x 4 ft. x 6 in. (0.94 m x 1.22 m x 152 mm) reinforced concrete slabs powered for 30 months at 10 mA/ft2, 20 mA/ft2, and 40 mA/ft2 (111 mA/m2, 222 mA/m2, and 444 mA/m2) under laboratory conditions using four different CP anodes.

    The investigation has provided new insights into the factors controlling the performance and longevity of the various cathodic protection systems.

    Keywords:

    Cathodic protection, corrosion, bridge decks, parking structures, chlorides, overlays


    Paper ID: STP12649S

    Committee/Subcommittee: C09.23

    DOI: 10.1520/STP12649S


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