Thermal, mineralogical and spectroscopic study of plasters from three post-Byzantine churches from Kastoria (northern Greece) (original) (raw)
Related papers
Minerals, 2020
The investigations focused on the façade of the 17th-century Myszkowskis chapel at the 13th-century Church of the Holy Trinity in Cracow, Poland. Most of the chapel's façade is made of rusticated limestone blocks, but its lower part is covered with cement render, and the basement consists of irregular pieces of limestone and sandstone, bound and partly replaced with cement mortar. The façade exhibited clearly visible damages: gray soiling of the surface, cracks, scaling, and efflorescence. The study presents characteristics of the cement render and mortar used for stone repair and/or substitution, as well as efflorescence from the lower part of the Myszkowskis chapel façade. The materials were analyzed with optical microscopy, scanning electron microscopy (SEM-EDS), Raman microspectroscopy, X-ray diffractometry (XRPD), and mercury intrusion porosimetry. The analyses demonstrated that the render covering some of the decayed limestone blocks was prepared using Portland cement (residual clinker grains represent alite and belite) as a binding agent, mixed with crushed stone as an aggregate. The cement mortar consisted of rounded quartz grains, rock fragments, and feldspars in very fine-grained masses of calcite and gypsum, also containing relics of cement clinker (alite, belite, ferrite, and aluminate). All these components point out the use of the ordinary Portland cement. Analyses of the efflorescence allowed us to distinguish several secondary salts, among others, thenardite, aphthitalite, and darapskite. The appearance of these phases is related to the composition and physicochemical properties of the building materials, atmospheric alteration agents, air pollution, and some other anthropogenic factors.
Chemical and Spectroscopic Investigation on the Plaster of a Byzantine Church
Annali di Chimica, 2005
The discovery of a Byzantine church under the floor of one of the oldest churches of Salerno (Italy) has given us the opportunity to investigate the fine composition of the plaster through chemical and spectroscopic methods. In particular, considering that plasters are generally formed by a carbonate phase (carbonates) and an inert phase (silicates), the characterization, performed on the carbonate phase by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), has revealed the presence of dolomite minerals. This information indicates that, during the building process, some accessory minerals of marble were added in the mortar to be used like fillers. The carbonate phase makes too difficult the spectroscopic characterization of the inert phase. Only by acid attack of the plaster the inert phase has been isolated and its characterization, by XRD and optical microscopy, has indicated the presence of olivine minerals and other typical silicates of river sands.
10th International Symposium on the Conservation of Monuments in the Mediterranean Basin, 2018
The relocation of excavated monuments raises serious conservation and ethical problems. Although in situ preservation is usually preferred, in some case, the relocation of finds is inevitable for various reasons. Tomb 313, a roman monument found near Corinth in 2012 during the construction of a major motorway, has been relocated to a new position in the premises of the Archaeological site of Ancient Corinth since it was impossible to be preserved in the excavation site. The tomb was decorated by wall paintings, depicting garlants, fruits and three figures, two men and a woman, found in excellent state of preservation. Although the tomb has been externally insulated during the excavation and transport, its state of preservation decreased radically after the relocation. The microclimate of the tomb retained high relative humidity but gradually the wall paintings were cover by salt efflorescence. In order to estimate the risk and the actions needed to prevent damage, it was necessary to execute rapidly diagnostic techniques. For this reason, mapping and evaluation, in situ non-destructive testing was performed on the monument by means of IR Thermography along with examination of soluble salts samples by means of Scanning Electron Microscopy and X-ray Diffraction. Results obtained by the IRT monitoring suggest the existence of high moisture accumulation on the salt infected side of the tomb. The IRT examination of the wall paintings showed that moisture penetration is probably transporting salts from the immediate environment. Salt analysis showed that the origin of the salts is probably the concrete slabs that have been used for the reinforcement of the monument during transport. Due to the high relative humidity environment, gypsum salts were transported to the surface of the wall paintings and crystallize as efflorescence without the generation of damage. The results also suggested the future actions for the preservation of the wall paintings and the exhibition of the monument. IRT monitoring is a fast and reliable diagnostic technique that can provide a solid basis for salt weathering investigations.
Geological Quarterly, 2019
The study was aimed at min er al og i cal and geo chem i cal char ac ter is tics of sec ond ary phases re lated to de te ri o ra tion of his - toric build ing ma te ri als. The in ves ti ga tions, car ried out in the Holy Trin ity Ba sil ica in Kraków, Po land, fo cused on the south ern facade of the 17th-cen tury Myszkowskis Cha pel, built of the Mio cene Piñczów lime stone. Lower part of the facade is cov ered with a ce ment ren der, and the ex posed foun da tions are made of Ju ras sic lime stone and Cre ta ceous sand stone, both of lo cal or i gin from the Kraków re gion and neigh bour ing Carpathians, in the form of ir reg u lar blocks bound with a ce ment mor tar. The wall sur face ex hib its clear signs of dam age; from dark grey soil ing and scal ing to efflorescences. Sam pled ma te ri als, de te ri o - rated, al tered crusts and efflorescences were an a lysed with op ti cal and scan ning elec tron mi cros copy, X-ray dif frac tion, and Raman microspectroscopy meth ods. The sec ond ary min er als dis tin guished in clude abun dant gyp sum CaSO4·2H2O, less com mon thenardite Na2SO4 (and/or mirabilite Na2SO4ÿ10H2O), aphthitalite (K, Na)3Na(SO4)2, darapskite Na3(SO4)(NO3)·H2O, ettringite Ca6Al2(SO4)3(OH)12·26H2O, monosulphite Ca4Al2O6SO3·11H2O, as well as scarce ni tre KNO3, nitratine NaNO3 and ha lite NaCl. Gyp sum usu ally forms sur face crusts and fills the pores in side some ma te ri als. The efflorescences, sam pled from the ex posed foun da tions, con sisted of thenardite and/or mirabilite, aphthitalite and darapskite, whereas ettringite and monosulphite were con nected with ce ment ren ders. Traces of ni tre, nitratine and ha lite were de tected at var i ous el e ments of the cha pel facade and foun da tions. The or i gin of the salts is re lated to com po si tion and physicochemical prop er ties of the build ing ma te ri als, as well as to anthropogenic fac tors. Key words: stone de te ri o ra tion, sec ond ary salts, aphthitalite, darapskite.
Environmental Geology, 2005
This work analyzes the stone superficial deterioration of some monuments in Rabat city. The rock is a calcarenite with porous texture, rich in calcium carbonates and fossils. The techniques used to study the surfaces altered by blackening or black crusts, are the SEM equipped with EDX microprobe, the X-ray diffraction, and the analysis of the soluble salts by ionic chromatography for anions and flame spectrometer for cations. They reveal significant contents of calcium sulphates, mainly gypsum, often associated with sodium chlorides. These salts known to have a destructive effect on the calcareous stones seem to be originated from the contamination by atmospheric pollutants, particularly sulfur dioxide, and by the marine sprays.
Building and Environment, 2007
In this study, we investigated the chemical and physical properties of the volcanic rocks used as building stones in historical places and monuments. The chemical weathering effect of salt crystallization on these stones was measured on the laboratory conditions (in most cases, used samples were very small). For this purpose, the dry weight loss (DWL) test was conducted. The rocks of dacite, andesite and tuffs of volcanic origin have different durability against salt crystallization. The most stable rocks are dacites (DWL 2.06%) which were used in the construction of Hittite monuments at Eflatun. The durability of the stones is closely related to their chemical, mineralogical, petrographical and mechanical properties. The stones used in the historical buildings are generally much more stable than present-day building stones. r
Characterisation of the progression of salts in walls of earthen architecture heritage
Mineralogical Magazine, 2022
Two hundred years (1750-1950) of earthen architecture represents an important period of construction in the central region of Portugal. Earthen architecture is usually built close to the coast or to rivers and placed in sandy ground. The impact of rising damp is a general problem and efflorescences are a common cause of damage decay. This problem was studied in a building with two types of earthen construction, adobe masonry walls and formed masonry walls. The aim of this research was to characterise the conditions for the appearance and phase transitions of thénardite and mirabilite, and determine how to prevent progression of salt effects in the two types of wall to support future conservation measures. Laboratory capillarity and porosimetry tests with dolomitic air lime mortar and hygrothermal monitoring were pursued along with in situ tests. Visual assessment showed that the progression of salts depends on the composition of the earthen materials. To understand these differences, all crystalline solid phases were analysed by powder X-ray diffraction, and building interior hygrothermal conditions were monitored. An investigation into the influence of surface lime water painting and sacrificial mortar application on the crystallisation of sodium sulfates concluded that these also depend on the wall's composition. Data allowed us to conclude that inside the building the temperature and humidity [relative humidity (RH = 100 p w /p°w > 70)] conditions led to the adobe breakdown by the fast conversion from thénardite to mirabilite. Therefore, contact with wet atmospheres should be avoided and interior hygrothermal conditions should be controlled. Laboratory and in situ tests showed that the environmental conditions of the spaces had effects on the results. The results contribute to understanding of the salt progression and pattern of decay, as well as supporting future recommendations for building conservation, based on the identification of environmental conditions proper to their occurrence.
TG-DTA and FTIR analyses of plasters from byzantine monuments in Balkan region
Journal of Thermal Analysis and Calorimetry, 2006
Historic plasters from wall paintings of Byzantine and post-Byzantine churches situated in the Balkan region were studied. All wall paintings were made with fresco technique and are dated from IX-XVI century. Plaster samples were followed from room temperature to 1000°C by Thermogravimetric (TG) and Differential Thermal Analysis (DTA), and one or two significant temperature regions, corresponding to thermal decomposition mechanisms were observed. The analysis of the plaster samples and the composition characterization was carried out using also, Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). Although the main components are calcite and quartz (from sand) in different proportions, there are differences between them such as the presence of gypsum being either as a constituent element or due to environmental pollution. The results are examined comparatively taking into account the creation time and place of the paintings.
Trends Journal of Sciences Research, 2015
The sanctuaries of Demeter and Asklepios are part of the Dion archaeological site that sits among the eastern foothills of Mount Olympus. The main building materials are limestones and conglomerates. Sandstones, marbles, and ceramic plinths were also used. The materials consist mainly of calcite and/or dolomite, whereas the deteriorated surfaces contain also secondary and recrystallized calcite and dolomite, gypsum, various inorganic compounds, fluoroapatite, microorganisms and other organic compounds. Cracks and holes were observed in various parts of the stones. The influence of specific weathering agents and factors to the behavior of the materials was examined. The particular environmental conditions in Dion combine increased moisture and rain fall, insolation and great temperature differences, abundance of intensive surface and underground water bodies in the surrounding area, an area full of plants and trees, therefore, they can cause extensive chemical, biological and mechanical decay of the monuments. The following physical characteristics of the building materials have been studied: bulk density, open porosity, pore size distribution, water absorption and desorption, capillary absorption and desorption. The chemical composition of bulk precipitation, surface and underground water was investigated. The salts presence and crystallization was examined. The influence of the water presence to the behavior of the materials was examined by in situ IR thermometer measurements. Temperature values increased from the lower to the upper parts of the building stones and they significantly depend on the orientation of the walls. The results indicate the existence of water in the bulk of the materials due to capillary penetration. The existence of water in the bulk of the materials due to capillary penetration, the cycles of wet-dry conditions, correlated with the intensive surface and underground water presence in the whole surrounding area, lead to partial dissolution-recrystallization of the carbonate material and loss of the structural cohesion and the surface stability.
Heritage Science
This paper focuses on the diagnosis of damage processes of decorative Roman renders of a group of tombs in the Porta Nocera necropolis in the ancient city of Pompeii, Italy. Unprotected from various climatic events, the tombs keep on deteriorating since they were first excavated in 1954. Extensive on-site and laboratory diagnostics using non-destructive and low-destructive techniques have been able to demonstrate that soluble salts are among the major agents of deterioration, causing damage in the form of render delamination. Gypsum is formed on the surface of the materials by the deposition of sulfur dioxide, resulting in reduced porosity and hardening of the surface. Soluble salts of nitrates and chlorides that penetrate the tombs’ masonry from the ground and are transported through the render layers tend to crystallize in subsurface. The crystallization—dilution cycles of the soluble salts cause major mechanical pressures, leading to the progressive destruction of the renders. Pa...