Nuno Gonçalo Leal

Different Mediterranean Basin limestones, like Calcário Ançã (Portugal), Calcário Lioz (Portugal), Piedra San Cristobal (Spain), Piedra Escúzar (Spain) and Pietra di Lecce (Italy), have been widely used as building materials in the European architecture. The aim of this study was focused on biodeterioration, mainly on evaluation of the primary bioreceptivity of those materials. A set of samples was inoculated with a cultured photosynthetic biofilm under laboratory conditions. Several assessment tools were applied to monitor the colonization overtime of the different lithotypes. After 3 months of incubation the colonization occurred endolithically in some litho-types, namely Piedra San Cristobal and Piedra Escúzar. Spectrophotometric determination of chlorophyll a was a useful analytical technique to achieve the total amount of photosynthetic biomass on rock substrates, demonstrating that Piedra Escúzar and Calcário Lioz were the highest and lowest bioreceptive lithotypes, respectively. Microscopic and image analyses were essential to understand the stone colonization process and its pattern of distribution. Physical stone parameters and exposure conditions were shown to play an important role in the establishment and development of photosynthetic colonization.

Stone materials used in the construction of the Spanish Fortress of Bizerte (Tunisia), show a high degree of alteration. Samples of these rocks, calcarenites, were collected and treated with different consolidants. Then, they were subsequently subjected to salt spray test with ventilation, in order to test the effectiveness of the products under these conditions. The results obtained from the samples mass loss and macro and microscopic inspection made possible to compare the performances of the different consolidants. These studies allow to predict the behavior of these stony materials in the field and to decide the best application in the rocks present in monuments, optimizing solutions for conservation and restoration. Os materiais pétreos de construção da Fortaleza espanhola de Bizerte (Tunísia), apresentavam elevado grau de alteração. Amostras destas rochas, calcarenitos, foram recolhidas e tratadas com diferentes consolidantes. Posteriormente foram submetidas ao ensaio de nevoe...