TIME-RESOLVED MICROWAVE THERMOREFLECTOMETRY FOR EVALUATION OF DIELECTRIC-METAL INTERFACES

A new method is described which uses the change in microwave reflectio n of metals after induction heating to characterize the metal-coating interface. Preliminary results with this technique are presented for a materials system consisting of a steel reinforcing bar (rebar) inside a cylinder of concrete. A portion of the length of the rebar has been insulated from the surrounding concrete with foam insulation in order to simulate the presence of corrosion at the rebar-concrete interface . The microwave thermoreflectance technique is used to characterize th is specimen and the results are compared with finite element calculati ons.