Water content of limestones submitted to realistic wet deposition: a CIME2 chamber simulation

An experimental chamber (CIME2) has been specially designed to simulate wet atmospheric deposition on limestones used in Paris cultural heritage. This instrument is a complementary tool to CIME, a previously developed chamber dedicated to the simulation of dry atmospheric deposition on monuments and artifacts. The aim of this paper is to describe CIME2 and characterize the wet deposits produced inside it. Mist (fog), drizzle, and rainfall are differentiated in order to document their ability to saturate the limestones most currently used in Paris monuments: The Saint-Maximin's limestone, the Liais of Saint-Maximin, and the Chauvigny's limestone are tested. The comparison between normalized and environmental petrophysical data shows that in the wet deposition simulations, limestones are not systematically water-saturated. Moreover, the realistic experimental conditions chosen favor a more rapid evaporation of the stone water. The quantification of the non-saturation state is a first step that has to be taken into account to improve the geochemical models used to predict the alteration.