Applied mineralogy in the study of historical lime mortars

376 p. (V.I); 581 p. (V. anexos)This PhD thesis aims to contribute towards a better understanding and conservation of Architectural Heritage through applied mineralogy in the study of historical lime mortars. To achieve this aim there search approaches the study of the lime mortars from different historical buildings in northern Spain,by combining a series of mineralogical, chemical and physical analytical techniques. Aggregates naturein the studied mortars differed in each historical building and depending on the building structures pointing to a specific selection of the raw materials, which are mainly conditioned by the surrounding geological materials. Sample preparation and the accurate mineralogical characterization of mortar binder have been essential to achieve more reliable radiocarbon ages. It has been demonstrated that thelayered double hydroxides phases (LDHs) constituted a potential contaminant mineral phase for mortarradiocarbon dating. The obtained results also provided valuable information about technologicalknowledge in mortar manufacture and application techniques, such as the use of both the traditional hot-mixing method in the manufacture of mortars and the multi-layering application technique. The high porosity and water absorption capacity, poor pore interconnection or difficulty in drying have beenthe main causes for studied lime mortar deterioration susceptibility, although environmental conditions to which are exposed also makes them susceptible to potential water and salts damage. The present study lays the foundations for the design of repair mortars that ensure the conservation of studied castles in future restoration works

Praktika zientifikoen integrazioa sustatzen: geologia ikasgeletan

This study presents an experience aimed at promoting the integration of scientific practices in the classroom during compulsory education, promoting the learning of geology and help to improve students’ attitude towards science. To this end, a didactic sequence was designed and carried out to address contents related to the geosphere and minerals in an active way. The results show an improvement in the students’ attitudes and highlights the need to introduce activities that encourage active learning in geology

La geosfera y sus minerales: desarrollo de una unidad didáctica

Este trabajo comienza con una introducción donde se realiza tanto una presentación personal, una presentación del currículo académico como una descripción del contexto del centro donde se han realizado el practicum I y practicum II. A continuación, se presenta el análisis didáctico de dos actividades realizadas en la asignatura de Diseño de actividades de aprendizaje en biología y geología del máster y su aplicación en el practicum II para posteriormente exponer la propuesta didáctica en relación a la geosfera y sus minerales. Tras presentar las actividades llevadas a cabo en el desarrollo de la unidad didáctica, se expone un análisis de los resultados de aprendizaje. Finalmente, se exponen unas consideraciones finales en relación a la experiencia tanto en el máster como en el practicum I y practicum II.<br /

Petrographic and Chemical–Mineralogical Characterization of Mortars from the Cistern at Amaiur Castle (Navarre, Spain)

Mortars from the cistern in Amaiur Castle (Navarre, Spain) were analysed to assess the mortar manufacturing process and application techniques. To this end, optical microscopy, scanning electron microscopy (SEM), thermogravimetric analysis, X-ray fluorescence (XRF), X-ray diffraction (XRD), Raman microspectroscopy, and Fourier transform infrared spectroscopy (FTIR) were performed. The study of both structural and plaster mortars from Amaiur Castle cistern show patterns/rules in the mortar manufacture according to the specific construction requirements. A multilayer application technique was used for the construction of the cistern tank. Deliberate selection of the aggregate nature and grading contributed to mortar impermeability. Ceramic and silico-aluminous rock fragments were used as aggregates in the cistern tank to confer hydraulicity to the mortars, instead of carbonated aggregates as used in the vault. Aluminosilicated phases present in the aggregates led to the formation of amesite, which is a magnesium aluminosilicate hydrate (M-A-S-H) phase conferring hydraulicity to the mortar. Two types of additives were identified in the outer pigmented layer of plaster. Beeswax was the identified organic additive used to improve the impermeability of mortar, while hematite was the identified inorganic additive giving rise to the reddish colour of the layer.This research was funded by the IT1193-13 project of the Basque Government

Mineralogical, Textural and Physical Characterisation to Determine Deterioration Susceptibility of Irulegi Castle Lime Mortars (Navarre, Spain)

Archaeological lime mortars from the Tower Keep and West perimeter wall of Irulegi Castle (Navarre, Spain) were analysed to determine susceptibility to deterioration. Chemical, mineralogical, textural and physical characterisation was performed by different tests and multianalysis techniques in order to determine the intrinsic features of the original historical mortars at the castle. Samples from the Tower Keep are more prone to deteriorate compared with the West perimeter wall due to high water absorption capacity and high porosity. A high degree of pore interconnection, high desorption index and the presence of high pore volume in the 0.01 to 1 mu m size range affect the mortar durability since pores retain water longer inside the mortar. Local environment conditions with persistent annual rainfall, high humidity and temperature variations contribute to the decay process of the original mortar. Characterisation of historical mortars not only allows better understanding of susceptibility to deterioration but also helps the design of compatible and durable repair mortar for future interventions on historical heritage. Compatibility of new materials with the historical mortar will be ensured by studying mortar characteristics and properties.This study was possible thanks to the financial support of Junta de Andalucia Research Group RNM179 and Research Project MAT2016-75889-R

Hydrotalcite and Hydrocalumite in Mortar Binders from the Medieval Castle of Portilla (Álava, North Spain): Accurate Mineralogical Control to Achieve More Reliable Chronological Ages

Mortars from different stratigraphic units at Portilla Castle (Alava, North Spain) have been analyzed for mineralogical characterization before radiocarbon dating. The mortar binder at Portilla Castle is composed not only of neoformation calcite but also of double-layered hydroxide (LDH) minerals such as hydrotalcite and hydrocalumite. The mineralogy of several fractions of the binder has been analyzed to determine the granulometric distribution of minerals in the binder. The continuous monitoring of mineralogy during the extraction of different grain size fractions has been performed by using a scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analyses (TGA). Hydrotalcite and hydrocalumite-bearing mortar binders give older ages than expected since they introduce dead carbon into the system.This research was possible thanks to the financial support of SAI13/106 research project of Basque Country Government

Compositional Characterization and Chronology of Roman Mortars from the Archaeological Site of Arroyo De La Dehesa De Velasco (Burgo De Osma- Ciudad De Osma, Soria, Spain)

This study characterises the mortar materials used in the construction of walls and floors at the Arroyo de la Dehesa de Velasco site, located near the Roman city of Uxama Argaela (the modern Burgo de Osma—Ciudad de Osma, Soria, Spain). Multilayer mortars have been characterised by petrographic, mineralogical (X-ray diffraction and scanning electron microscopy with energy dispersive analyses and geochemical analysis (X-ray fluorescence). Additionally, radiocarbon dating of the mortar binder fraction was performed in order to establish the chronology of the building in the absence of other archaeological chronological records. The results showed that similar siliceous aggregates and lime binders were used in the fabrication of multilayer system mortars. Some multilayer wall mortars show ceramic fragments or brick powder to produce hydraulic mortars and improve the resistance to moisture. The raw materials used for the construction of the site were of local origin and the construction was built during the first century BC, according to radiocarbon dating.This study was partially supported by the T1193-13 project of the Basque Country Government

Hydrotalcite and Hydrocalumite in Mortar Binders from the Medieval Castle of Portilla (Álava, North Spain): Accurate Mineralogical Control to Achieve More Reliable Chronological Ages

Mortars from different stratigraphic units at Portilla Castle (Alava, North Spain) have been analyzed for mineralogical characterization before radiocarbon dating. The mortar binder at Portilla Castle is composed not only of neoformation calcite but also of double-layered hydroxide (LDH) minerals such as hydrotalcite and hydrocalumite. The mineralogy of several fractions of the binder has been analyzed to determine the granulometric distribution of minerals in the binder. The continuous monitoring of mineralogy during the extraction of different grain size fractions has been performed by using a scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermogravimetric analyses (TGA). Hydrotalcite and hydrocalumite-bearing mortar binders give older ages than expected since they introduce dead carbon into the system

Characterization of Historic Lime Mortars from the Arch of San Martin to Identify the Construction Phases of the City Wall of Burgos (Spain)

Historical lime mortars provide valuable information on the construction phases of buildings and allow reconstruction of the chronology of the historical structures. The City Wall of Burgos and the Mudejar Arch of San Martin were declared an Asset of Cultural Interest and have been protected since 1949. Several restorations at the end of the 20th century altered the original appearance of the wall and the current gate, making it difficult to establish stratigraphic relationships between the two structures. Given the scarcity of information on the construction phases of the wall and the uncertainty of the historical dates, a mineralogical and chemical characterization of the mortars was carried out, and the suitability of the binder for radiocarbon dating was assessed. The petrographic, mineralogical and chemical analyses of the lime mortars from the Arc of San Matin show distinctive characteristics, suggesting different construction periods and production processes, where the selection of raw materials and production methods was conducted according to the construction requirements. Moreover, the presence of contaminant phases and microparticles of charcoal in the binder fraction led to discard all the samples for mortar radiocarbon dating