DETECTION OF INTERFACIAL FLAWS BETWEEN STEEL PLATES AND CONCRETE MEMBERS USING THE THERMOGRAPHIC TECHNIQUE

Abstract

This paper describes a nondestructive method to evaluate the size and depth of interfacial defects between the concrete members and the enclosing steel plate by the infrared thermographic technique. In this procedure, in order to investigate the influence of a defect in a thermography, liquid nitrogen is used to cool the surface of the steel plate. Its thermal distribution are measured. From these measurements, it is possible to estimate the diameter of circular defects from the calculated inflection points in the thermal distribution curve. The process to evaluate the depth of the defects by using the relation between the volume of the defects and proposed thermal parameters is also presented.