Quantitative analysis of plastered mosaics by means of active infrared thermography

Abstract

The aim of this study was to experimentally and numerically demonstrate the potential of cooling down thermography on revealing and quantitatively characterising hidden mosaic layers, located beneath different covering interventions. Images seeing-through the mortar on plastered mosaic surfaces were obtained using the principles of cooling down thermography, while quantitative information regarding the hidden structures were retrieved through the simultaneous conduction of experimental testing and the conduction of numerical parametric studies, evaluating the influence of specific parameters alterations on the plastered mosaics thermal response. Both experimental and numerical testing were performed based on the assumption that infrared thermography will be able to detect the hidden mosaics, presented with temperature variations on the surface, due to the dissimilar thermal diffusion that each layer renders, while quantitative analysis was performed correlating the retrieved numerical and experimental results. The results of this study verified that cooling down thermography can be considered as a valuable appraisal tool for plastered mosaic investigations, as mosaics detection was possible from the experimental measurements. On the other hand, the combination of experimental and numerical results can expand its capabilities for quantification purposes as promising results were produced regarding the estimation of mosaic depth, thickness and thermophysical properties.