Development of a new non-destructive testing technique for quantitative evaluations of delamination defects in concrete structures based on phase delay measurement using lock-in thermography

Abstract

A new quantitative NDT technique for delamination defects in concrete structures was developed based on the phase delay measurement using a lock-in infrared thermography under the application of periodical heating. It was found that the location and size of the defect can be estimated from the contrast change and that the depth can be estimated from the relationship between phase delay and heating period.