Infrared thermography technique (IRT) for the evaluation of the hydric behavior of building stones

Abstract

The water distribution into stone specimens in laboratory conditions is evaluated through the infrared thermography method (IRT). Porous building stones samples (calcarenite and sandstone) are examined under stable laboratory conditions (controlled temperature and relative humidity) in order to simulate the same hydric behavior in real scale of material systems in situ. Hydric tests monitored through IRT are performed in order to analyze the capillary water absorption and evaporation transport phenomena into stone samples. IRT technique allows to record thermal images at different intervals of time highlighting the internal capillary and evaporation rise heights, responsible for the majority of decay processes occurring in masonries. The geometric shape of the damped area and the time of spreading are directly related to the open porosity of the investigated stone materials. Hydric tests are repeated for each splitting plane of the specimens (faces), in order to obtain useful results that could be applied for real masonries. Results demonstrate the usefulness of IRT as a non-destructive and portable technique in the field of new construction and for restoration purposes, as well as its importance in characterizing the physical stone features and the effectiveness of applied conservation treatments.