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1 Expert-Center pour la Conservation du Patrimoine Bâti, EPFL MX-G, CH-1015 Lausanne, Switzerland benedicte.rousset{at}epfl.ch
2 Laboratoire de Mécanique et d’Acoustique, Chemin Joseph Aiguier, F-13402 Marseille Cedex 20
3 Centre de Géochimie de la Surface — EOST, 1 rue Blessig, F-67084 Strasbourg Cedex
Drying experiments were conducted under controlled conditions (relative humidity, temperature, motionless atmosphere) using Fontainebleau sandstone. X-ray computed tomography images acquired at various stages of the drying show that the location of water in the pore network depends on the method of initial saturation. After capillary absorption, the trapped air, or free porosity, allows the water distribution to be homogeneous and independent of the pore structure. This is because it homogenizes the tensions that apply to the water in the pores, regardless of the pore dimensions. However, this is not the case after a total saturation under vacuum. These differences are visible from the beginning to the end of the drying experiments. These results are important for curators or restorers of the architectural heritage, because they show that before testing a conservation product for stones, the method of saturation of these stones must be considered and attention should be given to the required effect.
