Investigation on porosity changes of Lecce stone due to conservation treatments by means of x‐ray nano‐ and improved micro‐computed tomography: preliminary results

TLDR

Cultural heritage materials, such as Lecce stone—a biocalcarenite with high porosity—undergo chemical and physical changes like black crust formation, corrosion, and cracking when exposed to environmental conditions. The study aims to evaluate how hydrophobic organic conservation treatments affect Lecce stone by examining changes in porosity and internal structure. Researchers used micro‑x‑ray computed tomography to characterize untreated and treated samples, calculated porosity and related parameters, and employed sub‑micron resolution x‑ray tomography to visualize product distribution within pores. Results show that conservation treatments alter the stone’s porosity and internal structure, with measurable changes before and after application and visible distribution of the hydrophobic products inside the pores. © 2007 John Wiley & Sons, Ltd.

Abstract

Abstract Cultural heritage materials are subject to continuous chemical and physical changes depending on the establishment of a dynamic equilibrium with the environment in which they are placed. In particular, different phenomena can take place, such as formation of black crusts, corrosion of the material, internal cracks. Lecce stone, a biocalcarenite mainly used for historical buildings in South Italy, has a high total porosity. In order to prevent its deterioration, different kinds of hydrophobic organic products are applied on the surface of the restored artefacts. Since the efficacy of the treatments depends mostly on the penetration depth and the distribution of the products in the pores, porosity and internal structure of the stone material were mainly investigated in this research. Micro x‐ray computed tomography (µ‐CT) has been used to study and characterize the internal structure of different samples, untreated and treated with protective products. The porosity and other parameters of the rock were then calculated and compared, before and after the conservation treatment, in order to highlight the changes due to the application of the product. On the other hand, small pieces of the untreated and treated samples were analysed by sub‐micron resolution x‐ray tomography where it was possible to see the distribution of the products inside the pores. Copyright © 2007 John Wiley & Sons, Ltd.