New evidence of early use of artificial pozzolanic material in mortars

Hydraulic building composites, such as mortars and plasters, produced with artificial pozzolanic materials, became widely popular thanks to the Romans. Reports on earlier uses of such composites can also be found, mainly in archaeological and historic documents. These date back as far as the time of Minoan and Mycenaean civilizations. Here, we present a holistic analytical investigation of Late Bronze Age mortars from various archaeological sites of Cyprus. We focus on petrographic observations of thin sections, scanning electron microscopy and energy dispersive X-ray microanalyses and we investigate the microstructure and texture of the samples and the chemical composition and interface of their binders. Results of powder X-ray diffraction analyses are also presented, alongside a series of measurements using mercury intrusion porosimetry and vacuum saturation, aiming to estimate the pore size distribution and the physical properties (i.e. open porosity and bulk density) of the specimens under investigation. We also report on tests carried out to assess the drilling resistance of the mortars using a novel, portable system. The results thoroughly confirm, for the first time, the earliest intentional use of crushed brick as an artificial hydraulic additive in lime mortars in Cyprus, in order to enhance their performance and longevity in the absence of natural pozzolanas.     

A non-invasive study of Roman Age mosaic glass tesserae by means of Raman spectroscopy

Ancient mosaic tesserae are a range of materials of very varied and complex nature, including pottery, stone and glass. Raman spectroscopy is a powerful tool for the analysis of all these kinds of materials. In the particular case of glasses, this technique can be used both for a study of surface weathering and for the characterization of bulk structure, but it has not yet been extensively used for the characterization of mosaic glass tesserae. We carried out Raman analyses on a set of Roman and Late Antiquity period mosaic glass samples, which allowed a good characterization of both the glass matrix and the crystalline inclusions. All the samples show the typical Raman signatures of soda-lime-silicate glasses. Several crystalline phases were also identified, being relics of raw materials used during the glass manufacturing process, such as quartz and feldspars, or linked to the glass color/opacification, such as bindheimite and cuprite. The analyses also led to the identification in some blue, turquoise and green tesserae of calcium antimonate, whose Raman signature has only recently been recognized in the scientific literature on mosaic glasses. Some emphasis is given to the analysis of red lead-containing tesserae, colored with Cu⁺ ions or even Cu⁰ (or Au⁰) metal nanoparticles. Samples with peculiar compositions, as well as “modern” (and restoration) samples, could quite easily be distinguished from the ancient ones by their Raman spectra.     

ANALYTICAL CHARACTERIZATION OF ROMAN PLASTERS OF THE ‘DOMUS FARINI’ IN MODENA*

The paper refers to the analytical characterization of Roman painted plasters dating back to the second century ad . The following techniques were used: optical microscopy (OM), scanning electron microscopy (SEM–EDS), micro‐Raman and Fourier transform infrared spectroscopies (µ‐Raman and FT–IR), X‐ray diffraction (XRPD), colorimetry and thermal analyses (TG/DTA). The investigation analysed the chemical composition and structure of the plasters, the chemical composition of the pigment layers, the use of binders and any chemical alteration of pigments as well as deterioration of the samples. Stratigraphic analysis of plasters allowed identification of their individual components, which proved helpful in finding out more about the mural painting technique employed.     

唐张臣和墓彩绘陶质文物的拉曼光谱和X衍射分析

利用拉曼光谱和X衍射方法,对张臣和墓彩绘陶质文物颜料及胎体进行分析,结果表明各种颜料保存基本完好,为以后科学保护修复这批彩绘陶质文物提供了科学依据。同时也证明,在样品量极少的情况下,利用拉曼光谱和X衍射等方法可有效鉴别古代颜料的种类及文物胎体的成分。     

A comparative study of wall paintings at the Cypriot monastery of Christ Antiphonitis: one artist or two?

The central church of the monastery of Christ Antiphonitis near Kalogrea, within the district of Kyrenia in Cyprus, is decorated with wall paintings that date from the last decades of fifteenth century. Two large and elaborate scenes, the Last Judgement and the Root of Jesse, had been preserved in the church until the Turkish invasion (1974) after which they were cut into tetragonal pieces, separated, and sent by looters to Germany for selling at illicit markets. The German Police returned thirty-two of the pieces to the Archbishop Makarios Foundation in Nicosia.     

Effect of natural polymers from cissus glauca roxb on the mechanical and durability properties of hydraulic lime mortar

The tradition of using lime as a binder has been in practice over the centuries and is cited in the architectural feats of all kinds of civilizations. Besides the basic ingredients of lime, sand and water, organic admixtures were also mixed into the mortars to modify fresh and hardened state properties as well as to enhance its durability. The motivation of the present study was to develop a replacement of synthetic admixtures by the bio-admixtures. The plant extract of Cissus glauca Roxb (CGR) which is being used in ancient temples and monuments in Kerala has been tested as admixture in varying concentrations and fermentation periods in lime mortar mix. The admixture is polysaccharide rich and a moisturizing agent.

Tests were conducted to measure changes in microstructure of the mortar; fresh state properties such as setting time and workability, mechanical properties such as compressive strength and flexural strength. Also, physical characteristics of admixture modified mortars such as bulk density, porosity and water absorption were also determined. Morphological analysis using SEM with EDX, mineralogical analysis using XRD and organic analysis adopting FT- IR have been done to validate the results of mechanical and physical tests. Capillary water and salt absorption by suction and resistance to salt crystallization cycles were measured as an indicator of durability properties.

The admixture modified mortar resulted in increased mechanical properties and reduced water absorption. It also limits the capillary rise of water and salt intrusion through the hydrophobic nature. The admixture modified mortar have also offered better resistance against the damaging action of deteriorating salts such as sodium chloride and sodium sulphate crystallization cycles. Polysaccharides and proteins in the plant extract interact with the calcium hydroxide of slaked lime and forms complexes. Hence the, natural polymer has increased the durability of hydraulic lime mortars used for repair and it could be a natural alternative to synthetic admixture.     

Characterization of prehispanic cosmetics found in a burial of the ancient city of Teotihuacan (Mexico)

The present paper reports the chemical data obtained on samples of pigmenting materials contained in 31 miniature vessels found in a burial found in Teopancazco, a multiethnic neighborhood center located in the southeastern sector of the archaeological site of Teotihuacan (Central Mexico) and the analytical protocol established for the complete characterization of these archaeological materials. For this purpose a multi-technique approach based on the combination of several non destructive and micro-destructive instrumental techniques, namely, light microscopy (LM), scanning electron microscopy-X-ray microanalysis (SEM-EDX), transmission electron microscopy (TEM), voltammetry of microparticles (VMP), X-ray microdiffraction (μXRD), X-ray diffraction (XRD), UV-Vis spectrophotometry, FTIR spectroscopy and gas chromatography-mass spectrometry (GC-MS) has been developed in an attempt to completely characterize these materials. These instrumental techniques provide reliable and complementary data including elemental and mineralogical composition, identification of functional groups as well as speciation studies of electroactive species. Among the most relevant findings, volcanic pyroclastic rocks and clayey soils, most probably, from the Teotihuacan valley as well as galena, jarosite and mica from other provenances in Mesoamerica, have been identified. Charcoal and Ocote resin have also been identified. The chemical composition of the samples is discussed with a view to the possible function as cosmetic materials and their use in funerary rites. The results have been critically compared with those others obtained in other ancient civilizations. The study carried out on the materials found in the burial 105 is especially relevant insofar it represents the first evidence, scientifically characterized, of the use of cosmetics in Mesoamerica at this early period (AD 200-550).