Caracterização de revestimentos de imitação de pedra em stucco-marmo com vista à sua preservação

Abstract

Stucco-marble is one of the most representative decorative techniques of the Baroque period in Europe. It intends to imitate stone architectural coatings. In Portugal, between the mid‑18th century and the mid‑20th century its use was much more frequent than previously thought. The lack of information regarding these coatings endangered their preservation. To fill this gap, a survey was made in the literature on the history and terminology related to stucco‑marble and buildings where it was used were identified. Samples were collected and the mineralogical composition using x‑ray diffraction (XRD) was determined. Physical and mechanical properties, namely capillary water absorption and dynamic modulus of elasticity, were also studied. In this paper, the results obtained are presented and discussed. They allowed concluding that most of the samples are made of gypsum‑anhydrite plaster, with physical and mechanical characteristics very similar to those of the materials they intend to imitate. Terminology issues are also debated. This study aims at contributing to the preservation of a decorative technique of outstanding patrimonial value.