Detection and quantification of discontinuities in building materials using transient thermal NDT techniques : Modeling and experimental work

In this work, active infrared thermography was employed in the investigation of various building materials. Different types of building materials were assessed: three types of porous stone (from Rhodes, Cyprus and Rethymno-Crete) and one type of marble (Dionysus). The investigated samples contained self-induced discontinuities of known dimensions and depths. During the investigation, the specimens were heated externally (thermal excitation) and thermograms were recorded continuously at the transient phase. Mathematical thermal modeling enabling the modeling of the investigated subsurface discontinuities, using 3D software, was also implemented. Then, quantification analysis (that is, temperature versus time plots, as well as thermal contrast curves) from the experimental tests, as well as from the use of thermal modeling runs took place, indicating the thermal behavior of building materials containing such discontinuities.