Time-Resolved Microwave Thermoreflectometry for Infrastructure Inspection

This paper describes the development of time-resolved microwave thermoreflectometry (TRMT) as a potential NDE technique for the detection of corrosion of reinforcing bar (rebar) in concrete structures. The approach in this technique is as follows: rebar inside a concrete structure is heated in a noncontacting fashion using an induction heating source; the temperature of the surface of the rebar is monitored directly through the concrete using a microwave reflectometer; degradation of the structural integrity of the bond between the concrete and the rebar affects heat flow from the heated rebar to the surrounding concrete.</p