The applicability of pulse phase thermography (PPT) for the investigation of structures is studied systematically on concrete test specimens and on a plastered sandstone column. In the test specimens, voids and delaminations are implemented in different depths and with different sizes, modelling real voids, honeycombing and debonding. Delaminations of plaster in concrete and masonry and behind tiles on concrete are investigated. PPT is based on the frequency analysis of the cooling down process of actively heated surfaces. Therefore, it is contactless and thus completely non-destructive (if overheating of the surface is prevented), fast and allows the inspection of large surface areas. The interpretation of amplitude and phase images gives semi-quantitative information about the observed defects. The phase images provide a deeper probing up to 10–15 cm in relation to the interpretation of the thermograms and to the amplitude images. In addition, the influence of surface inhomogeneities and non-uniform heating is reduced.RésuméL'applicabilité de la thermographie de phase pulsée à l'examen de constructions est systématiquement étudiée sur des échantillons de béton et sur une colonne de grès plâtré. Dans les échantillons testés, des vides et des délaminations sont opérés à différentes hauteurs et différentes tailles, modélisant les vides réels, l'instabilité et la décohésion. Les délaminations de plâtre dans le béton et les maçonneries et derrière les sont examinées. La thermographie de phase pulsée est basée sur l'analyse de la fréquence du processus de refroidissement des surfaces activement chauffées. L'absence de contact la rend donc complètement non-destructive (dès lors que l'on empêche de la surface d'être surchauffée) et rapide. Cette méthode permet l'inspection de grandes surfaces. L'interprétation de l'amplitude et des images de phase fournit des informations semi-quantitatives sur les défauts observés. Les images de phase sondent plus profondément jusqu'à 10–15 cm en relation avec l'interprétation des thermogrammes et des images d'amplitude. De plus. l'influence des inhomogénéités des surfaces et de la chaleur non uniforme est réduite.
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