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Projeto de investigação
Novo: Argamassas em Monumentos Históricos contribuições para a preservação do Património Cultural Edificado. Inicial: Cimentos e Argamassas em Monumentos Históricos: contribuições para a preservação do Património Cultural Edificado
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Mortars from the palace of Knossos in Crete, Greece
Publication . Carvalho, Fernanda; Sousa, Pedro; Leal, Nuno; Simão, Joaquim A. R.; Kavoulaki, Elissavet; Lima, Maria Margarida; Silva, Teresa Pereira; Águas, Hugo; Padeletti, Giuseppina; Veiga, João Pedro; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; DCT - Departamento de Ciências da Terra; DCR - Departamento de Conservação e Restauro; MDPI - Multidisciplinary Digital Publishing Institute
The study of building materials constituting cultural heritage is fundamental to understand their characteristics and predict their behavior. When considering materials from archaeological sites, their characterization can provide not only relevant information for a broader understanding of the site and its importance and significance but can also increase knowledge about ancient materials and their performance. The Palace of Knossos is a very important archaeological site in the European history context, and its preservation benefits from the characterization of the constituent materials. Samples of mortars from this monument were collected under the scope of the H2020 HERACLES project, where a multi-analytical approach was chosen using established protocols for the different sample typologies. Instrumental techniques such as optical microscopy (OM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and simultaneous thermogravimetry and differential thermal analysis (TG–DTA) were used for the chemical, mineralogical, and morphological characterization of these mortar samples. The results indicate that the majority are lime mortars, both aerial and hydraulic, but gypsum-based mortars were also identified. Differences in the chemical composition of the samples in distinct areas of the monument allowed us to reflect on the variety of materials used in the construction of the Palace of Knossos.
Historical lime‐based flooring mortars from the Church of Santa Maria de Alcobaça monastery (12th century), Portugal
Publication . Carvalho, Fernanda; Nunes, Ana; Pagará, Ana; Costeira, Isabel; Silva, Teresa Pereira da; Lima, Maria Margarida Rolim Augusto; Veiga, João Pedro; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCM - Departamento de Ciência dos Materiais; DCR - Departamento de Conservação e Restauro; Blackwell Publishing Ltd
The Monastery of Alcobaça houses in reserve the ceramic tiles that adorned the floor of the church's apse. These tiles were removed during rehabilitation works and many preserve part of their original fixing mortars. A comprehensive analysis of 21 samples was conducted using a multi-analytical approach (X-ray fluorescence, X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray spectroscopy, μ-Raman spectroscopy, thermogravimetry–differential thermal analysis, optical microscopy, and colorimetry). Results suggest compositional variations in the samples from the back and sides of the ceramic tiles; however, the mineralogy and general characteristics of the aggregates remained consistent between the samples and are coherent with the local geology, suggesting a shared historical origin.
The Mortars of Built Cultural Heritage
Publication . de Carvalho, Fernanda Barroso Bruno; Sousa, Pedro; Leal, Nuno; Simão, Joaquim; Kavoulaki, Elissavet; Lima, Maria Margarida; da Silva, Teresa Pereira; Águas, Hugo; Padeletti, Giuseppina; Veiga, João Pedro Botelho; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); GeoBioTec - Geobiociências, Geoengenharias e Geotecnologias; DCT - Departamento de Ciências da Terra; DCR - Departamento de Conservação e Restauro; MDPI - Multidisciplinary Digital Publishing Institute
The study and characterization of mortars is generally related to the knowledge of the properties of the material, which guarantee or improve its performance and durability. When we consider the study of historical mortars, the main objective is to understand the characteristics of the material and how it has reached the present day, considering that, often, the time of its preparation and application is separated from the present by a long period of time, perhaps centuries, and is thus difficult to specify. This type of study may give indications on historical issues relevant to the understanding of a particular site or monument and, in addition, can assist in actions related to its preservation. Mortars can be used with different functions, ranging from structural function, protection, or finish, which requires distinct properties that are suitable for this functionality. It is necessary to consider that the desired characteristics, after drying the mortar, will depend on a set of factors, including the selection and quality of the raw material, the proportion between the main components, the way they are prepared and applied, and the environmental conditions they will be subjected to over time. Furthermore, the larger the monument is, the greater the chances of changes, reconstructions or interventions, including materials prepared in different periods with different raw materials and techniques. This is precisely the case of the Palace of Knossos, located near the Heraklion in Crete. It is estimated that the first palace was built in 2000 B.C.; however, it was destroyed and rebuilt more majestically in 1700 B.C. The definitive abandonment of the palace would have occurred around 1450 B.C., but the site where it was built maintained its importance for many centuries. Excavated at the beginning of the 20th century, the Palace of Knossos is one of the most important archaeological sites in Europe, both for its size and the complexity of its plant, with architectural solutions worthy of a well-developed civilization, as well as for the many reclaimed materials and frescos found. In addition to all of the material wealth found in its excavation, the palace has undergone peculiar historical conservation including the reconstruction of many of its structures, even as late as the early 20th century, all considered of great importance for the history of the monument. For this study, samples of mortars were collected at different points of the Palace of Knossos, both from areas of archaeological remains as well as from reconstructed areas. For the characterization, we opted for a multi-analyses approach which involved optical microscopy observation, X-ray fluorescence, X-ray diffraction, FTIR, -Raman, simultaneous thermogravimetry and differential thermal analysis. The results obtained indicated that the samples were mostly lime mortars with different hydraulicity indexes produced from local raw materials. The results also indicated that the samples presented considerable differences depending on the area in which they were collected, showing the variety and complexity of the materials produced in different periods, even when used for the same function.
Orange pickeringite from the algares 30-level adit, aljustrel mine, iberian pyrite belt, portugal
Publication . Silva, Teresa P.; Matos, João X.; de Oliveira, Daniel; Morais, Igor; Gonçalves, Pedro; Albardeiro, Luís; Carvalho, Fernanda; Menda, Ugur D.; Veiga, João P.; DCM - Departamento de Ciência dos Materiais; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N); DCR - Departamento de Conservação e Restauro; MDPI - Multidisciplinary Digital Publishing Institute
The sheltered environment of the Algares +30 level adit (underground mine gallery) contributes to the preservation of secondary water-soluble minerals formed on the tunnel walls. The massive sulphide and related stockwork zone are hosted by the Mine Tuff volcanic unit and are exposed in the walls of the gallery, showing intense oxidation and hydrothermal alteration. Minerals from the halotrichite group were identified on the efflorescent salts, typically white fine-acicular crystals but also on aggregates with dark orange/brownish colour. Mineral characterization was performed using several methods and analytical techniques (XRD, XRF-WDS, SEM-EDS, DTA-TG), and the chemical formulas were calculated maintaining the ratio A:B∼= 1:2 in accordance with the general formula of the halotrichite group, AB2 (SO4 )4·22H2 O. This methodology allowed the assignment of the orange colour to the presence of trivalent iron on iron-rich pickeringite in partial substitution of aluminium.
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Fundação para a Ciência e a Tecnologia
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SFRH/BD/145308/2019