Читать книгу Monument Future - Siegfried Siegesmund - Страница 380

Water content in stone is of primary relevance for the preservation of cultural heritage. High water content promotes the development of microorganisms and causes mechanical or physico-chemical alterations by swelling/shrinkage or dissolution/recrystallization of salt. The identification and then the control of the water transfer remain important to assess the risk of damage. A good prediction of the water content helps to develop some preventive action dedicated to the conservation of Heritage.

The most accurate methods to measure water content require sampling and can only exceptionally be used. Few methods are non-destructive, but their accuracies are often limited.

The aim of this study concerns the application of Non-Destructive Technics (NDT) to determine the water distribution within the building masonry, in particular the infrared imaging and electrical method.

The electrical method enables to image the spatial and/or temporal variation of the electrical properties related to the water content distribution in the materials while infrared thermography provides the boundary limit conditions by the means of surface thermograms. Those methods are performed for several samples used as building materials in the archeological site of Vaux de la Celle (Genainville, France). The site concentrates various structures built between the 2nd and 4th century AD. The temple structure is constructed at the lowest part of the valley with its foundations in direct contact with the vadose zone where the water table fluctuates. Reproducibility and reliability are also provided through several experimental configurations.