2010 Volume 59 Issue 3 Pages 75-79
The goal of this paper is to evaluate the environment within concrete nondestructively related to corrosion of reinforcing bar using the newly developed magnetic corrosion probe which is introduced into concrete to raise a magnetic signal. The probe was prepared by electroplating of iron onto a copper bar, which was subsequently heat treated at 423 K for 30 min to stabilize the residual magnetization. The residual magnetization from the probe, as detected by superconducting interference device (SQUID) decreased with progress of corrosion of the probe. The electrochemical behavior of the magnetic corrosion probe was also evaluated in a saturated Ca(OH)2 solution. The as plated probe showed a large active current density and residual magnetization. The heat treatment of the probe resulted in reduction of the active current density and residual magnetization. Meanwhile the passive current density of the probe was still higher as compared with that of an iron bar even after the heat treatment. This means that the probe is more sensitive to corrosive environment than reinforcing bars. Thus, the developed probe is expected to give a magnetic warning against degradation of surroundings in advance of the corrosion of reinforcing bar.