MICROWAVE NONDESTRUCTIVE EVALUATION

OF FIBER REINFORCED POLYMER WRAPPED CONCRETE

STRUCTURES

Yoo Jin Kim¹, Maria Q. Feng1, and Kevin Park¹

ABSTRACT

This paper presents an innovative nondestructive evaluation (NDE) technology and

development of the portable microwave equipment for composite structures including fiber

reinforced polymer (FRP) wrapped concrete, focusing on the detection of debonding, void, and

delaminations of FRP and concrete interface. The technology is based on the reconstruction of

microwave signal profile on the scanned surface by sending toward and receiving back from the

structure. Electrical material characters such as permittivity and loss factor were identified on

several types of FRP and concrete, which serve as a foundation for determination of the system

parameters and analysis of the performance. The microwave NDE equipment consists of array

antennas as a microwave probe, signal source module, and a system controller. The system uses

X–band microwave source for high-resolution and portability of the array antennas, which has

high gain and narrow beamwidth. The system scans the surface of a structure by changing the

focused point of microwave beam either mechanically or electronically. Experimental results on

the several specimens showed the efficiency of the developed system.

1 Newport Sensors, Inc., Irvine, CA 92612, Email: yjkim@newportsensors.com