摘要: Laboratory studies examined the myriad parameters effecting corrosion ratemeasurements made by electrochemical means. The most important parameters found were: good electrical contact between the probe and the concrete surface; sy... 展开 Laboratory studies examined the myriad parameters effecting corrosion ratemeasurements made by electrochemical means. The most important parameters found were: good electrical contact between the probe and the concrete surface; symmetric positioning of the probe over the rebar; presence of a stable open-circuit (corrosion) potential; use of a guard ring of appropriate size and spacing (relative to the counter electrode) to define the polarized area; and the necessity of ensuring that measurements are carried out over the active part of macrocells. Three commercially developed corrosion rate devices were evaluated in the laboratory and the field. Two, GECOR and 3LP, operate on the linear polarization principle. The third, an NSC device, operates on the principle of superimposed current pulses of high and low frequency with current confinement. All gave comparable qualitative results for actively corroding conditions. Field tests were carried out at sites representing sub-tropical marine, mild and severe winter (deicing chemical) exposure conditions. Reproducibility was comparable among the three devices. The corrosion currents measured correlate with each other, although rather significant differences exist in magnitude. 收起