Efficiency evaluation of nano-structured consolidants on Carrara marble by field exposure tests.

In the context of a changing environment, the preservation of outdoor built heritage is increasingly threatened. Furthermore the application of conservation products does not always achieve the expected results. Furthermore, preliminary tests aimed at evaluating the performance of new products often show them to be inappropriate. In such situations, the paper reports the outcomes of an innovative methodology adopted to assess the efficiency and durability of nano-based consolidating products utilized for the conservation of carbonate artworks, carrying out field exposure tests on Carrara Marble model samples in different sites. Surface properties, superficial cohesion, distribution and penetration of the conservation products and their interactions with substrates and environmental conditions were examined and compared with the features of undamaged samples and of artificially damaged samples.