Electrode configurations for resistivity measurements on concrete

In this study, two- and four-electrode arrangements were used to evaluate the electrical resistance (hence resistivity) of saturated concrete specimens using both embedded rod-electrodes, external plate-electrodes, and combinations thereof. Measurements were obtained mainly at a fixed frequency of 1 kHz. It is shown that the two-electrode external plate measurement system gave higher resistivity values than the four-electrode system; however, studying the electrical response in terms of complex impedance, over the frequency range 1 to 10 MHz, revealed that the sponge-contacting system used in the two-electrode method introduced a spurious resistance attributed to the sponge-sample interface.