New nondestructive measurement for fiberglass-reinforced plastic mortar pipes using microwave and photonic techniques

A new nondestructive inspection method for fiberglass-reinforced plastic mortar (FRPM) pipes using microwave and photonic techniques is proposed. We found that FRPM pipes of 250~1000 mm in diameter and 20 mm in thickness can be a good cylindrical waveguide with single or a few guided modes for 1~10 GHz microwave and that the microwave transmission along a FRPM pipe is rather affected by defects in the FRPM pipe or its surface condition. With accurate measurement of a transmitted microwave signal using an electro-optic sensor, we expect to be able to detect defects or problems in FRPM pipes nondestructively.