Stucco marble in the Portuguese architecture: first insights in mineralogical, physical and mechanical properties

Author(s): Maria Teresa Freire, António Santos Silva, Maria do Rosário Veiga
Paper category: Proceedings
Book title: Proceedings of the 5th Historic Mortars Conference
Editor(s): José Ignacio Álvarez, José María Fernández, Íñigo Navarro, Adrián Durán, Rafael Sirera
ISBN: 978-2-35158-221-3
e-ISBN: 978-2-35158-222-0
Publisher: RILEM Publications SARL
Publication year: 2019
Pages: 211-225
Total Pages: 15
Language : English

Abstract: The magnitude of the presence of stucco marble in the Portuguese architecture is still not known and studies addressing the characterisation of the materials used to produce its complex coloured pastes are almost inexistent.
In this paper, the results of the mineralogical, physical, and mechanical analysis of twelve samples belonging to five case studies are presented and discussed. Gypsum is the main constituent, but anhydrite is also present in most samples in higher quantities than those found in common gypsum based plasters. A multiphase gypsum plaster was used as binder, possibly to improve the mechanical properties of the hardened pastes. However, in the case of stucco marble, the grinding and polishing operations of the surfaces used to obtain an aesthetical appearance similar to the natural stone have also a major influence in the main properties of the final materials.
The dynamic moduli of elasticity results are extremely high in the samples incorporating anhydrite and the capillary water absorption is almost inexistent. On the contrary, the samples without anhydrite have low absorption values but show absorption curves according to gypsum based plasters.
The results obtained constitute the first approach to the knowledge of ancient stucco marble coatings in Portugal and intend to contribute to the future development of compatible restoration products.

Online publication : 2019
Publication type : full_text
Public price (Euros) : 0.00

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