The CRATI Project: New Insights on the Consolidation of Salt Weathered Stone and the Case Study of San Domenico Church in Cosenza (South Calabria, Italy)

Abstract

This paper presents the results of a laboratory experimentation carried out on stone materials in the framework of the CRATI project (Knowledge and Restoration through Advanced Integrated Technologies) aimed at testing new products with consolidating properties by means of an integrated methodological approach. After the preliminary characterization of stone materials collected in the pilot site, the second stage of the activities within the project were focused on the formulation and testing of products for the conservation of the same materials against decay, especially salt crystallization, one of the most aggressive and common degrading processes. The San Domenico Church, located in the old town of Cosenza (Calabria, Southern Italy) has been chosen as the pilot site and for the in situ tests. Several specimens with the same features of the stone materials used in San Domenico church were collected from a historical quarry near the city of Cosenza. These specimens were treated and then artificially degraded by salt crystallization tests in order to evaluate their susceptibility to weathering intensity. Three different consolidating products were used; respectively, two commercial and another one formulated in laboratory: (a) a suspension of nanosilica (Nano Estel®); (b) a suspension of nanolime (CaLoSiL®), and (c) a suspension of nano calcium-hydroxide dispersed in isopropyl alcohol and then mixed with diammonium hydrogen phosphate. A systematic approach, including minero-petrographic, geochemical and physico-mechanical techniques, was applied to evaluate (a) the nature and main features of materials; (b) the efficacy of consolidating treatments, and (c) the resistance of treated stone to the salt crystallization processes. The tested products demonstrated a significant efficiency to consolidate and protect stone material samples, enhancing their resistance to salt crystallization. Thus, such a case history may be useful in order to plan appropriate restoration interventions that consider the interactions between the building stone and the protective/consolidating product.

Multi-Analytical Characterization of Corvins’ Castle—Deserted Tower. Construction Materials and Conservation Tests

“…and its preserving conditions (temperature, relative humidity, etc. ), for maintaining the aesthetic value, in agreement with the Venice Charter (1964) [23][24][25].…”

Multifunctional and Durable Coatings for Stone Protection Based on Gd-Doped Nanocomposites

“…However, historic building materials, in particular when exposed outdoors, are subject to many phenomena such as microorganisms colonisation which consequently cause a transformation and deterioration of art surfaces [1]. On the other hand, water, which is one of the most deteriorating factors especially for porous materials, air pollution, and dyes, which strongly adhere to the stone substrate [2][3][4][5], contribute to the decay of external historic buildings. Thus, conservation and protection of cultural heritage materials become a necessity in countries with tourism potential [4].…”

“…On the other hand, water, which is one of the most deteriorating factors especially for porous materials, air pollution, and dyes, which strongly adhere to the stone substrate [2][3][4][5], contribute to the decay of external historic buildings. Thus, conservation and protection of cultural heritage materials become a necessity in countries with tourism potential [4].…”

Decay Assessment of Stone-Built Cultural Heritage: The Case Study of the Cosenza Cathedral Façade (South Calabria, Italy)

“…It is a porous but resistant material with a variable chromaticity ranging from whitish to reddish hues. These variations are commonly induced by a different content of ferrous minerals although other causes cannot be excluded [12,13].…”