Quelltext der Seite Cit:Brunet-Imbault.etal:2017

== Abstract  ==
The Jacobine Church of Morlaix in France has been deconsecrated in the XIXth century. Afterwards, it has been used as a stable and then turned into a market which included salt storage for food preservation. Moreover, the church is built downhill of a significant slope next to the Jarlot river. The church, built with granite and schist, presents important salt resurgences, granular disintegrations and moisture areas on joint mortars. The project of the city is to restore the church and turn it into an exhibition space included in a new museum. According to this project, the architects want to apply new lime plasters on the walls, which is not possible because of the high levels of salts. In order to evaluate the salt contamination, samples have been taken in different heights and depths in stones and mortars. Contamination profiles have been obtained and poultices based on cellulose fibers, clays and fine quartz sand have been formulated. Stone and poultice porosimetries have been measured in order to adjust the poultice formulation. The goal of this adjustment was to obtain the appropriate pore size distributions to improve the moisture transport mechanisms between stones and poultices. Three poultices formulations containing variable ratios of cellulose, sand and clays have been selected. Test areas included join removal as much as possible and vacuum cleaning of the wall surface before the first poultice application. These on-site trials allowed us to study desalination efficiency, including poultice formulation and desalination practice (number of poultices applications, wall surface preliminary preparation). Granite cut stone and schist blocks masonries have distinct properties, so desalination practice must be adjusted to obtain an optimized efficiency, including a different poultice formulation and a different masonry preparation. Nevertheless, the desalination of such contaminated masonries is a challenge to preserve lime plaster from future degradations.

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