STP1056: Elimination of IR Error in Measurements of Corrosion in Concrete

    Escalante, E
    Metallurgist, National Institute of Standards and Technology, Gaithersburg, MD

    Pages: 11    Published: Jan 1990


    Abstract

    The deterioration of concrete bridge decks owing to the corrosion of imbedded steel has generated interest in developing techniques to measure the corrosion of steel in this high-resistivity environment. Several electrochemical polarization methods have been used successfully in the laboratory. This paper describes the use of current interruption to eliminate the IR that arises in measuring the potential of steel during polarization measurements.

    Polarization measurements were carried out using a small, portable computer system that controlled and monitored the potential of the steel and the applied current. Current was cycled on and off, with the potential measured during the off cycle and the current during the on cycle. The duty cycle was 2.2 s on and 0.4 s off, and sampling of the voltage occurred approximately 75 ms after the current was interrupted. Results indicated that 95% of the error is eliminated using this technique.

    Keywords:

    bridge deck corrosion, corrosion of steel, corrosion rate measurement, IR error, polarization resistance, steel in concrete


    Paper ID: STP25288S

    Committee/Subcommittee: G01.11

    DOI: 10.1520/STP25288S


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