Thickness determination of surface Protection systems for concrete by means of impulse thermography

In the building industry, polymer coatings on concrete are often used to create a certain appearance and to protect the component from aging, wear and tear, and damage. For practically all purposes, effectiveness depends on the specially defined thickness of the polymer coating. Therefore, the thickness of the coating is checked after the coating has been applied. However, so far only destructive testing methods have been available for the mineral substrate concrete, which is challenging in this context. For this reason, within the scope of the project IRKUTSK, a method based on active thermography was developed, as well as an instrument for on-site use, with the help of which nondestructive layer thickness determination is possible. Here, a brief insight into the thermographic method developed for the determination of coating thickness is given. The special features of quantitative evaluation, which occur due to the semi-transparency of polymer coatings, are explained. The function of the method for single-layer systems is illustrated by laboratory measurements using different optical sources for thermal excitation.