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In this article, the results of a treatment applied to dolomitic stones using an isopropyl colloidal solution based on calcium hydroxide nanoparticles with a concentration of 2.0g/l are presented. The consolidation process in the stone has been checked before and after 28 days of exposure to 75% relative humidity. Morphologic and structural studies of the consolidating product confirmed the carbonation process. X ray diffraction, electron microscopy (TEM and ESEM), and electron diffraction carried out on the consolidating product have confirmed the transformation of portlandite phase to calcium carbonate polymorphs, calcite, aragonite and vaterite. Petrophysical tests performed on the stone before and after the application of the product have shown the improvement in the physical and hydrical properties due to the increase in the ultrasound velocity and density of the material, and a decrease in the capillarity coefficient and open porosity without significant changes in colour and brightness. The application of the consolidating product in the proposed experimental conditions is a natural method, compatible with the petrological characteristics of the substrate, without secondary damages on the stone, being an effective method to improve the durability of carbonate stones.En este artículo se presentan los resultados del tratamiento aplicado a muestras de piedra dolomía mediante una solución coloidal isopropílica basada en nanopartículas de hidróxido de calcio en una concentración de 2,0g/l. El proceso de consolidación de la piedra ha sido monitoreado antes y después de su aplicación a los 28 días de estar expuesta a una atmósfera del 75% de humedad relativa. Se ha realizado un estudio morfológico y estructural del consolidante confirmándose el proceso de carbonatación. Los resultados de difracción de rayos X, microscopía electrónica (TEM y ESEM) y difracción de electrones realizados al producto consolidante han confirmado la transformación de la fase portlandita a los polimorfos de carbonato de calcio de tipo calcita, aragonito y vaterita. Los ensayos petrofísicos realizados a la piedra antes y después de su aplicación, han demostrado que se produce una mejora de las propiedades físicas e hídricas indicado por el aumento tanto en la velocidad de propagación de ultrasonidos como en la densidad del material y una disminución de su coeficiente capilar, así como de la porosidad abierta sin producirse modificaciones significativas en el color y el brillo. La aplicación del tratamiento de consolidación propuesto, con este tipo de soluciones coloidales de nanopartículas, es un método natural y compatible con las características petrológicas del sustrato, sin generar daños secundarios sobre la piedra, resultando un método eficaz para la mejora de la durabilidad de rocas carbonáticas.

The walled complex of Talamanca de Jarama has a long history of wars that have destroyed it several times. Due to this fact, the Wall has gone through many reconstruction and enlargement processes (9th, 13th, 14th and 17th century), to which the restorations performed during the last century (20th) must be added. The main building materials are bricks together with rammed-earth and stones. The bricks studied under Polarizing Microscopy (OM), X-ray powder diffraction (XRD), spectrocolourimetry, ultrasounds and mercury intrusion porosimetry (MIP), allowed us to distinguish five types, each of them belongs to different manufacturing periods. The oldest bricks (type I) and the most recent ones (type V), are those that differentiate the most. The five types of bricks show heterogeneities due to a deficient manufacture, which is responsible for their decay process, despite the fact that these bricks have been placed recently, during the last intervention.El recinto amurallado de Talamanca de Jarama tiene una larga historia llena de conflictos bélicos que lo han destruido en numerosas ocasiones. Por este motivo, la muralla ha sufrido numerosas etapas de reconstrucción y ampliación (s.IX, s.XIII, s.XIV y s.XVII), a las que hay que añadirle numerosas intervenciones de restauración en el último siglo (s.XX). Los ladrillos junto con los tapiales y las piedras son los principales materiales de construcción identificados. Los ladrillos estudiados por microscopía de luz polarizada (MO), difracción de rayos X (DRX), espectroscolorometría, ultrasonidos y porosimetria de intrusión de mercurio, han permitido diferenciar cinco tipos, pertenecientes a distintas épocas de fabricación. Son los ladrillos más antiguos (tipo I) y los más modernos (tipo V), los que más diferencias muestran entre sí. En general, los cinco tipos de ladrillos presentan heterogeneidades debidas a una fabricación deficiente y que son las responsables del proceso de deterioro que les afecta, aunque estos ladrillos hayan sido colocados recientemente, en la última intervención.

Brickwork from the Palacio del Infante Don Luis Antonio de Borbón (Boadilla del Monte, Madrid, 18th century) has been characterised, as well as the conservation degree of the materials has been determined. The original brick is of low quality and its mineralogical paragenesis shows firing temperatures of 750-850º C. Its high water absorption capacity and porosity are responsible for its characteristic alteration and disgregation. Restoration brick is of better quality, fired at higher temperatures (~900º C). In relation to the original mortar, it is a lime one, with a relation close to 1:2; aggregates are plurimineral and an average grain size of 1,50 mm. Mortars from following restorations are different from the original ones, not in composition, practically the same with the exception of the most modern mortar which is cementbased, but in their dosification and in the aggregates grain size, as well as in the finishing of the joint. Repointing of the original brickwork, together with the presence of water (dampness), and the low quality of brick due to an insuficient and heterogeneous firing, are resposible of the deterioration the brick undergoes.Se ha caracterizado la fábrica de ladrillo existente en el Palacio del Infante Don Luis Antonio de Borbón (Boadilla del Monte, Madrid, siglo XVIII), y se ha definido el estado de conservación de los materiales. El ladrillo original es de baja calidad y su paragénesis mineral indica una temperatura de cocción de 750-850ºC. Su elevada capacidad de absorción de agua y alta porosidad, son responsables de su alteración y disgregación. El ladrillo de restauración es de mejor calidad, cocido a mayor temperatura (~900ºC). En cuanto al mortero original, es un mortero de cal de relación cercana a 1:2; los áridos son pluriminerales y tamaño medio de 1,50 mm. Los morteros de las sucesivas restauraciones se diferencian del original, no en la composición, que es prácticamente la misma a excepción del más moderno, que presenta cemento, sino en la dosificación y en el tamaño de los áridos, así como en el acabado de la junta. El rejuntado de la fábrica de ladrillo original, junto con la presencia de agua (humedades) y la baja calidad del ladrillo debido a una cochura insuficiente y heterogénea, son los responsables del enorme deterioro que sufre el ladrillo.

Abstract: For hundreds of years, two types of granite (Zarzalejo and Alpedrete) from the Madrid region, Spain, have been extensively used as building stones. Fresh specimens of both stone types have been sampled from their respective quarries and subjected to sodium sulphate salt crystallization test (SCT). The resulting physical and chemical weathering patterns have been characterized by polarized light optical and environmental scanning electron microscopy. Water absorption under vacuum conditions and mercury intrusion porosimetry techniques were used to determine the pre- and post-SCT porosity and pore size distribution. The following non-destructive techniques were performed to assess stone durability and decay: ultrasound velocity (US) and surface roughness determination (SR) of intra- and inter-granular quartz, feldspar and biotite minerals at the centre as well as at the corners and edges of specimen surfaces. Before the SCT, US values were lower and SR values higher in Zarzalejo (ZAR) than Alpedrete (ALP) granite. After SCT, the US values declined while SR rose in both types of granites, with greater average differences in ZAR than ALP for both parameters. Feldspar and biotite and their inter-granular contacts were found to be the weakest and therefore the most decay-prone areas of the stone. The initial SR parameters were generally higher and rose more steeply after SCT at the corners and around the edges of the specimens. While behaviour was found to be similar in the two types of granite, variations were greater in ZAR, the less durable and more decay-prone of the two. Surface roughness measurement of mineral grains in granite stones is a very useful, in situ, non-destructive technique for quantifying salt crystallization-mediated physical and chemical weathering. The resulting quantification of decay and of related durability provides insight into the future behaviour of this type of stone, commonly used in historic buildings. [Copyright &y& Elsevier]

This article reports on a compositional investigation of stone patinas: thin colored layers applied for protective and/or aesthetic purposes on architectural or sculptural substrates of cultural heritage. The analysis and classification of patinas provide important information of historic and artistic interest, as their composition reflects local practices, the availabilities of different materials, and the development of technological knowledge during specific historical periods. Model patinas fabricated according to traditional procedures and applied onto limestone, and a historic patina sample from the main façade of the San Blas Monastery in Lerma (a village in the province of Burgos, Spain), were analyzed by laser-induced fluorescence and Fourier transform Raman spectroscopy. The results obtained demonstrate the ability of these two analytical techniques to identify the key components of each formulation and those of the reaction products which result from the chemical and mineralogical transformations that occur during aging, as well as to provide information that can aid the classification of different types of patinas.