Detection of Defects in Concrete Structures by Using Infrared Thermography

Abstract

This paper presents a report on the use of active infrared thermography in detecting and evaluating the extent of damage in concrete structures. Detection of sub-surface damages in concrete structures by the use of infrared thermography is becoming popular. This is because of advantages like non-contact testing and rapid scanning of any surface for damages. In this study active infrared thermography was conducted on laboratory casted concrete slabs with in-built defects of known sizes. It was found that the defects could be successfully identified by using infrared camera which outputs thermal images of the slab. Further, the images obtained were processed using a program to obtain area of defects. It was found that the defect area estimated had an error of about 32.5% with respect to the actual area. It was concluded that difference between area estimated and the actual area of defects can be minimized by employing adequate amount of thermal excitation.