PURPOSE: To perform the diagnosis of safety margin and estimation of residual life on an object to be inspected, by providing a container made of an electric insulator having an opening adapted to get tight on the object being measured at one end thereof and a reference electrode and an opposed electrode at the specified position in the center of the container.
CONSTITUTION: A reference electrode 7 is provided at the position 4W30mm inward from the tip of an opening in the center of a container while an opposed electrode 8 is at the position as far as more than 1.0 fold the inner diameter of the container behind the reference electrode 7. Then, a corrosion rate detection element 18 is fixed on the surface of a steel pipe pile 15 to be inspected with a fixing jig 17 incorporating a magnet 16 to determine a polarization resistance with a polarization device 13. An AC impedance method is used in this measurement. A potential is provided in a range of ±15mV from the natural dip potential at a measuring point by a sine function and the response of current thereto is measured to calculate the polarization resistance from the impedance obtained with respect to various frequencies from 1mHzW10kHz.
KIHIRA HIROSHI
ITO TORU
MURATA TOMOYOSHI
