X-ray microtomography as a non-destructive tool for stone characterization in a conservation study

Calcareous stones such as Lecce stones have a high porosity which results in a readily uptake of rainwater. Due to the atmospheric pollutants dissolved in the water these stones, used in a lot of historical buildings, are constantly under attack which leads to a decay of the stone. Different kind of organic hydrophobic products such as Paraloid B72 and fluorinated rubber are often applied as protectives with the aim to reduce the corrosion of the material. In order to study the manner in which these treatment products fill the pores a desktop X-ray microtomography system was used. This technique allows the 3D investigation of the internal structure of the stone in a non-destructive way. In this research morphological parameters such as the total porosity, pore size distribution, surface-to-volume ratio and structure model index were calculated before and after treatment in order to evaluate the changes induced by the polymer application.