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Although insoluble salts are one of the most common alteration forms that archaeological ceramics can present, the methods for their removal have not really changed within the past forty years. Furthermore, not many studies on the topic have been recently published. In this paper, a methodology to study the suitability of different traditional treatments for the removal of these salts, has been established. For this aim, ceramic mock-ups made out of a marketed red clay were fired up to 700ºC in an electric kiln. Their composition and physical properties were studied. Several tests were conducted in laboratory for the growth of calcium carbonate deposits similar to the ones that can appear naturally on archaeological ceramics. The method that provided the more alike deposits, was followed and applied onto the ceramic mock-ups. Different cleaning treatments based on three chemical products and three application methods were put into practice for the removal of such deposits. The products included two acids and a chelating agent and the application methods were direct and indirect, by immersion and using pulps and gels. The specimens’ characteristics were studied again to determine their changes due to the cleaning treatments. The analytical techniques of XRD and SEM, for mineralogical and elemental composition, microroughness, colour measurements, stereoscopic microscopy were used, and results showed efficacy differences linked to the product and application method. In general, the products applied by immersion and cellulose pulp poultice were more effective than gel treatments, which were less effective with any of the three products tested.

Grisolia is one of the building stones most commonly found in the architectural heritage of southern Italy. Also known commercially as “gold stone” for its yellow intrusions, Grisolia was employed by the leading Calabrian schools of stonemasons, principally in the southern Italian regions of Calabria and Basilicata. It is an Upper Triassic crystalline carbonate quarried in the Verbicaro Unit on Calabria’s northern Tyrrhenian coast. Possessing petrographic, physical and mechanical properties that ensure stone strength and durability, it is a high-quality building material suitable for structural and ornamental uses. These properties can be attributed to its low open porosity and excellent hydric behavior (low capillary water absorption), as well as to its high mechanical strength and low anisotropy. These characteristics make it recommendable as a building material for both restoration and new construction., La “piedra de Grisolia” es una de las piedras de construcción más utilizadas en el patrimonio arquitectónico del sur de Italia. También conocida comercialmente como “piedra de oro” por su color dorado, fue empleada por las más importantes escuelas de cantería, principalmente en las regiones italianas del sur, Calabria y Basilicata. Se trata de un carbonato cristalino del Triásico Superior extraído en la Unidad Verbicaro, en la costa Tirrénica del norte de Calabria. Gracias a sus propiedades petrográficas, físicas y mecánicas que aseguran su resistencia y durabilidad, es un material de alta calidad adecuado para fines estructurales y ornamentales. Estas propiedades se deben a su baja porosidad, excelente comportamiento hídrico - baja absorción capilar -, así como a su alta resistencia mecánica y baja anisotropía. Gracias a esas buenas propiedades, se recomienda su empleo como material de construcción tanto para la recuperación de edificios antiguos así como para la construcción de obra nueva.

The resistance of dolomitic limestone to salt crystallization processes was studied on materials from Redueña and Torrelaguna in the province of Madrid, Spain. Much of the region’s architectural and monumental heritage was built with the materials from these two sites. Stone specimens were selected for testing on the basis of ultrasonic wave propagation velocity (Vp) measurements taken in around one hundred cubic samples of each variety. The anisotropy indices were calculated and the samples were clustered on the basis of the results. Two representative samples of each class were taken and characterized for their petrographic and petrophysical properties before and after exposure to salt crystallization cycles. Ageing was evaluated in terms of weight loss and the visual deterioration observed. The degeneration pattern found varied substantially in the two materials: the Requena material exhibited more intense deterioration, with scaling and spalling, while the Torrelaguna dolostone tended to generate fragmentation and rounding at corners and edges. The anisotropy of these stones does not appear to clearly govern salt crystallization-mediated deterioration. Although no clear relationship could be established between the intensity of deterioration and the initial anisotropy indices, total anisotropy was observed to increase as a general rule, and normally more than the relative anisotropy index. No specific anisotropic group was found to undergo greater variation than any other.En este trabajo se estudia el comportamiento de las dolomías de Redueña y de Torrelaguna frente a los efectos de la cristalización de sales. Ambos materiales han sido ampliamente utilizados en la construcción del Patrimonio arquitectónico y monumental de la región de Madrid. Para la selección de las probetas pétreas a ensayar, se midió la velocidad de propagación de ondas ultrasónicas (Vp) en cerca de un centenar de muestras cúbicas de cada variedad. Se calcularon los índices de anisotropía y se realizó un proceso de clustering para su clasificación en función de niveles de anisotropía. De cada clase se tomaron dos probetas representativas y se procedió a su caracterización petrográfica y petrofísica antes y después de someterlas a ciclos de cristalización de sales. Para la evaluación del envejecimiento se registró la variación de peso y se documentó el deterioro visual observado. El patrón de degradación para cada uno de los materiales frente a los ciclos es bastante distinto: la dolomía de Redueña es la que presenta un deterioro más intenso con descamaciones y desplacados mientras que la de Torrelaguna tiende a generar fragmentaciones y formas redondeadas. La anisotropía de los materiales pétreos estudiados no parece controlar de forma clara el proceso de su deterioro por cristalización de sales. Aunque no ha sido posible establecer una relación clara entre intensidad de deterioro e índices de anisotropía iniciales, en general, se observa un incremento del índice de anisotropía total, por lo general algo menor para el índice de anisotropía relativa, sin poder apreciar que las variaciones sean mayores en un grupo de anisotropía específico.

This article reports on a study of Iberian, Italic and Tarraconensian amphora sherds found in different underwater marine environments. Non-desalinated fragments were compared to fragments desalinated using the procedure normally applied to underwater archaeological objects to study the efficacy of the method and determine both the state of conservation of the materials and the decay caused by salt weathering. To that end, destructive (X-ray diffraction, ion chromatography, scanning electron microscopy coupled to energy dispersive X-ray spectroscopy, mercury intrusion porosimetry) and non-destructive (computerized X-ray tomography) tests were conducted on the samples. The conclusion drawn was that the long-term salt content is closely related to firing temperature and that non-desalinated samples or samples in which desalination was not wholly effective exhibit a variety of signs of degradation that can be detected with computed tomography. CT proved to be a powerful technique for visualising and locating salts in the interior of porous materials. Keywords: Underwater ceramics, amphorae, desalination, salt weathering, durability

This study deals with the characterization of the pore structure of fresh quarry limestone samples belonging to the Mid-Eocene Mokattam Group, and porosity changes in samples subjected to salt crystallization tests at different temperatures (20, 30 and 40 °C) in a purpose-made simulation chamber based on feeding samples by capillary imbibitions. NaCl with fixed concentration (10%) was used in the different experimental tests. One more experiment was performed using only distilled water to discriminate changes due to salt crystallisation from those resulting just from wetting. In order to characterize the changes of the pore structure, fresh and weathered samples subjected to different temperature regimes tests were investigated by means of Mercury Intrusion Porosimetry (MIP), and Scanning Electron Microscopy (SEM). These results show the critical role of temperature in controlling the porosity changes after salt crystallisation. Key words: stone decay, limestone, salt weathering, pore structure

This paper presents the characterisation of salts found at the so-called ‘Silk Tomb’ one of thebuildings that form part of the Royal Tombs assemblage at the Nabatean city of Petra (Jordan),with the purpose of creating a specific data base of salts for this tomb that will allow the use ofportable non-destructive analytical techniques on it. The survey of efflorescences andsubefflorescences in this building revealed the presence of a wide variety of salts such as halite(NaCl), sylvite (KCl), niter (KNO3), gypsum (CaSO4•2H2O), syngenite (K2Ca(SO4)2•(H2O),polyhalite (K2Ca2Mg(SO4)4•2(H2O) and aphthitalite (K,Na)3Na(SO4)2 in different combinationsthat present a marked spatial distribution within a limited space. This reflects the variety ofinputs generated by human activities and natural sources in contrast with other, more secluded,monuments in which the mineralogy found is simpler.

The resistance of dolomitic limestone to salt crystallization processes was studied on materials from Redueña and Torrelaguna in the province of Madrid, Spain. Much of the region’s architectural and monumental heritage was built with the materials from these two sites. Stone specimens were selected for testing on the basis of ultrasonic wave propagation velocity (Vp) measurements taken in around one hundred cubic samples of each variety. The anisotropy indices were calculated and the samples were clustered on the basis of the results. Two representative samples of each class were taken and characterized for their petrographic and petrophysical properties before and after exposure to salt crystallization cycles. Ageing was evaluated in terms of weight loss and the visual deterioration observed. The degeneration pattern found varied substantially in the two materials: the Requena material exhibited more intense deterioration, with scaling and spalling, while the Torrelaguna dolostone tended to generate fragmentation and rounding at corners and edges. The anisotropy of these stones does not appear to clearly govern salt crystallization-mediated deterioration. Although no clear relationship could be established between the intensity of deterioration and the initial anisotropy indices, total anisotropy was observed to increase as a general rule, and normally more than the relative anisotropy index. No specific anisotropic group was found to undergo greater variation than any other., En este trabajo se estudia el comportamiento de las dolomías de Redueña y de Torrelaguna frente a los efectos de la cristalización de sales. Ambos materiales han sido ampliamente utilizados en la construcción del Patrimonio arquitectónico y monumental de la región de Madrid. Para la selección de las probetas pétreas a ensayar, se midió la velocidad de propagación de ondas ultrasónicas (Vp) en cerca de un centenar de muestras cúbicas de cada variedad. Se calcularon los índices de anisotropía y se realizó un proceso de clustering para su clasificación en función de niveles de anisotropía. De cada clase se tomaron dos probetas representativas y se procedió a su caracterización petrográfica y petrofísica antes y después de someterlas a ciclos de cristalización de sales. Para la evaluación del envejecimiento se registró la variación de peso y se documentó el deterioro visual observado. El patrón de degradación para cada uno de los materiales frente a los ciclos es bastante distinto: la dolomía de Redueña es la que presenta un deterioro más intenso con descamaciones y desplacados mientras que la de Torrelaguna tiende a generar fragmentaciones y formas redondeadas. La anisotropía de los materiales pétreos estudiados no parece controlar de forma clara el proceso de su deterioro por cristalización de sales. Aunque no ha sido posible establecer una relación clara entre intensidad de deterioro e índices de anisotropía iniciales, en general, se observa un incremento del índice de anisotropía total, por lo general algo menor para el índice de anisotropía relativa, sin poder apreciar que las variaciones sean mayores en un grupo de anisotropía específico.

The use of stone materials in cultural heritage and architecture represents a practice that has its roots in ancient times. Stone buildings, depending on the construction materials and their location in the urban context, are particularly vulnerable to weathering phenomena. These can be often accelerated by changes in environmental conditions linked mostly to the anthropic activities. In this way, the present work is addressed on the minero-petrographic and geochemical characterisation of samples taken from the built historical heritage in Cairo (Egypt), related to seven monumental areas. These sites have been chosen based on their historical importance, type of material, state of preservation and position in the Cairo context. The construction materials used and their degradation products were studied comparing the results obtained by means of different analytical techniques such as polarised light optical microscopy (POM), ion chromatography (IC), Fourier transform infrared spectroscopy (FT-IR) and the carbonaceous fraction, detected by using the thermogravimetry (TG). The results achieved demonstrated that black crusts and salt crystallisation represent the most common and damaging degradation products affecting all the monumental sites. Moreover, the environmental pollution produced by industrial activities and vehicular traffic has been identified as the main cause of these processes, followed by a marginal contribution of natural sources such as the sea spray. The data collected provide useful information to plan efficient conservation strategies in the future.

In the last decades, many researchers investigated the relation between environmental pollution and the degradation phenomena on the built heritage, because of their rapid increase and growing harmfulness. Consequently, the identification of the main pollution sources has become essential to define mitigation actions against degradation and alteration phenomena of the stone materials. In this way, the present paper is focused on the study of the effect of air pollution on archaeological buildings in Historic Cairo. A multi-methodological approach was used to obtain information about the chemical composition of examined black crusts and to clarify their correlation with the air pollution, specifically the heavy metals and the carbonaceous fraction, their main sources, and their impact on the state of conservation of the studied sites. All specimens were characterized by polarized optical microscopy (POM), X-Ray Diffraction (XRD), Electron Probe Micro Analyser coupled with energy dispersive X-ray spectrometry (EPMA-EDS), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and Thermo-gravimetric analysis (TGA). The study conducted on heavy metals and carbonaceous fraction showed that the greatest contribution of the accumulation of pollutants is attributable to vehicular traffic and industrial activities, the main polluting sources in Cairo city. Furthermore, the comparison with other studies conducted on the carbonaceous fraction in the black crusts coming from both European and non-European cities, has allowed to discriminate the contribution of the primary and secondary polluting sources. Finally, the correlation of the data obtained on the heavy metals and the carbonaceous fraction allowed to formulate important hypothesis about the processes of sulphation.

This work is focused on a multidisciplinary study of 13 pottery fragments collected in the submerged archaeological site of Baia (Naples, Italy). Founded by the Romans in the 1st century B.C., this archaeological area represents one of the greatest evidences of Roman architecture and it includes ancient ruins whose structures range from maritime villas and imperial buildings. Several diagnostic tests were carried out in order to characterize the archaeological materials, their structure and properties, as well as the alteration and degradation products. Degradation forms in seawater imply not only a variation in the physico-mechanical and chemical properties of the material but also an aesthetic damage, due to superficial deposits, which can lead to the illegibility of the artefacts. In this context, it is crucial to determine to what extent these decay factors, mainly attributable to biological growth, could affect the durability of pottery and what are the effects of cleaning procedures. The work offers further elements to obtain new insights into the underwater cultural heritage field and in the function of ceramic matter, especially related to several applications in technology and in the adoption of strategies for suitable conservation procedures.

We report the presence of bacterial colonization in library environment and on the books housed, performing morphological and bacterial molecular analyses. Isolated bacterial colonies were characterised by 16S rRNA locus and ITS (16S-23S rRNA Intergenic Transcribed Spacer) amplification and sequencing. The results of SEM observation and molecular analysis showed the prevalent presence of bacteria belonging to the family Micrococcaceae. We distinguished Kocuria rosea, Arthrobacter nicotianae, Micrococcus luteus and Curtobacterium flaccumfaciens which shows high cellulolytic activity.

International audience; The importance of capillary imbibition and evaporation processes in the decay of stone through salt crystallization is estimated by different experiments adapted from the European standard EN 12370. The various tests consist in slightly modifying the salt (sodium sulphate) supply in the porous network of stones as well as the amount of evaporation and in checking the weathering evolution of the stone. The results show that ionic diffusion and dissolution of pre-existent salts are not efficient enough to imply supersaturation, hence to visually alter the stone. An exterior supply of salt is required. The influence of evaporation is clearly shown when evaporation process could not occur through a side of the sample. In this case, isolated sides are never subjected to weathering, even to simple salt efflorescences

The rock/atmosphere interface is inhabited by a complex microbial community including bacteria, algae and fungi. These communities are prominent biodeterioration agents and remarkably influence the status of stone monuments and buildings. Deeper comprehension of natural biodeterioration processes on stone surfaces has brought about a concept of complex microbial communities referred to as "subaerial biofilms". The practical implications of biofilm formation are that control strategies must be devised both for testing the susceptibility of the organisms within the biofilm and treating the established biofilm. Model multi-species biofilms associated with mineral surfaces that are frequently refractory to conventional treatment have been used as test targets. A combination of scanning microscopy with image analysis was applied along with traditional cultivation methods and fluorescent activity stains. Such a polyphasic approach allowed a comprehensive quantitative evaluation of the biofilm status and development. Effective treatment strategies incorporating chemical and physical agents have been demonstrated to prevent biofilm growth in vitro. Model biofilm growth on inorganic support was significantly reduced by a combination of PDT and biocides. © 2006 Taylor & Francis Group. (13 refs.)

The present paper focuses on the results obtained from the investigation on the soiling affecting surface monuments and relie fs of important Iranian archaeological sites. For this purpose, samples of surface deposit and damage layers were collected on immovable cultural relics located in the provinces of Khuzestan and Fars, in Southern Iran. Different analytical techniques were applied with the aim of characterising the mineralogical composition of the damage layers, investigating the embedded atmospheric particles, measuring the soluble salt concentration, identifying and quantifying the carbon components present. The results obtained will be presented, paying particular attention to the carbon fractions not linked to the carbonate substrate, but originated by biological agents and anthropogenic activities. The quantitave data of non carbonate carbon, comprising both elemental and organic fractions, obtained through the application of the methodology set up during the CARAMEL EC Project, as well as the organic composition of the soiling deposits (investigated by thermally assisted hydrolysis and methylation and gas chromatography-mass spectrometry) will be illustrated and discussed., The authors gratefully acknowledge the researches of the Research Center for Conservation of Cultural Relics (RCCCR) of Teheran for the support and collaboration during the sampling campaigns.