A SIMPLE ARRANGEMENT AND PROCEDURE FOR IN-SITU MEASUREMENT OF CORROSION RATE OF REBAR EMBEDDED IN CONCRETE

An arrangement for the in-situ measurement of the corrosion current de nsity, i.e. corrosion rate, of rebar embedded in concrete through a li near polarisation technique is described. It incorporates a simple exp erimental method being suggested for determination of the ohmic resist ance of concrete, which enables the ohmic drop to be eliminated mathem atically from the polarisation data. The error due to nonuniform distr ibution of the applied electric signal through a small size counter el ectrode to the working electrode (rebar) is removed by using the trans mission Line model. A calculation procedure for estimating Tafel slope s has also been suggested for precise estimation of the Stern-Geary co nstant. The utility of the arrangement and the experimental procedure suggested for in-situ corrosion rate measurement is demonstrated throu gh a carefully planned experimental scheme.