CHARACTERIZATION OF PLASTERS AND MORTARS AS A TOOL IN ARCHAEOLOGICAL STUDIES: THE CASE OF LARDIRAGO CASTLE IN PAVIA,NORTHERN ITALY*

Plasters and mortars from Lardirago Castle (Pavia, northern Italy) have been characterized by means of petrographical and chemical analyses in order to achieve technical and historical evidence of material production. The study focused on the oldest nucleus of the structure, where hidden plastered masonry has been discovered recently. Textural and compositional data of the binder and the aggregate fractions were collected by means of optical microscopy and electron microscopy coupled with microanalysis. These data permit the identification of building materials with similar technical and compositional characteristics, which can be related to different building phases.     

GEOCHEMICAL CHARACTERIZATION OF ARCHAEOLOGICAL LIME MORTARS: PROVENANCE INPUTS*

Chemical and mineralogical analyses were carried out on historical lime mortars from the parish church of Santa María La Real (Guipúzcoa). The study included various periods ranging from Roman to modern times and allowed the identification of various types of raw materials. In order to obtain pure binder, free of carbonate aggregates and charcoal particles, an innovative binder separation method was implemented. The chemical composition of the binder allows discrimination of different provenance areas for the raw materials, although those areas do not correlate with specific historical periods. In addition, the influence of burial processes on the primeval chemical features has been assessed and reveals that modern mortars display greater chemical modification than the Roman mortars.     

RADIOCARBON DATING OF MORTARS FROM ANCIENT GREEK PALACES

This study deals with radiocarbon dating of lime mortars which were used as supports for Mycenaean and Minoan paintings. The ¹⁴C dates are. on the whole, compatible with the historical data. and thus show that a large proportion of the Mycenaean surficial coatings can be dated by the radiocarbon method. However. in order to determine the age of the mortars accurately. it is necessary to evaluate the amount of sedimentary carbonate which may have been added to them. It is shown here that the oxygen and carbon isotope compositions of lime mortars are significant indicators that such a mixing actually took place.     

DATING ANCIENT LIME MORTARS BY GEOCHEMICAL AND MINERALOGICAL ANALYSIS

This paper proposes a method of dating based on the study of the mineralogy and geochemistry of lime mortars. If the mortars used in constructing the various parts of a building are made from limestones of distinct geochemistry (minor elements) and mineralogy (clay content), such differences should be identifiable in their compositions. Furthermore, if some parts of the building can be reliably dated, the mortars used in their construction can be compared with mortars taken from parts of the building whose dates are unknown. Under certain conditions, a relationship can be established between the mortars, and a date may be proposed. An experimental procedure, based on identification of mortar phases, is proposed. The method was tested on two historical monuments, built in the eleventh to twelfth and nineteenth centuries respectively, which illustrate different dating problems.     

BUILDING MATERIALS OF THE THEATRE OF MARCELLUS,ROME*

The building materials of the Theatre of Marcellus, 44–11 bce , reflect Roman builders' careful selections of tuff and travertine for dimension stone and volcanic aggregates for pozzolanic concretes. The vitric–lithic–crystal Tufo Lionato tuff dimension stone contains a high proportion of lava lithic fragments, which increase its compressive strength and decrease water sorption, enhancing durability. Sophisticated installations of travertine dimension stone reinforce the tuff masonry, which is integrated with durable concrete walls and barrel vaults. The pozzolanic mortars of the concretes contain harenae fossiciae mainly from the intermediate alteration facies of the mid‐Pleistocene, scoriaceous Pozzolane Rosse pyroclastic flow. They have pervasive interpenetrating pozzolanic cements, including strätlingite, similar to high‐quality, imperial era mortars. Concrete walls are faced with refined Tufo Lionato opus reticulatum and tufelli, and opus testaceum of fired, greyish‐yellow brick. The exploratory concrete masonry, which includes some of the earliest examples of brick facings and strätlingite cements in Rome, and the integration of these materials in complex architectural elements and internal spaces, reflect the highly skilled workmanship, rigorous work‐site management and technical supervision of Roman builders trained in republican era methods and materials.     

Paper 6: Grouting Mortars for Fragmented Bricks and Repair Mortars for Tiles in the Archaeological Site Coudenberg

Abstract

Different grouting and repair mortars were developed and evaluated for the conservation and restoration of fragmented bricks in the walls and floors of the remaining cellars underneath the Aula Magna, the palace’s main banqueting hall, and to fill the lacunae and perform edge repairs of red and blue-grey ceramic floor tiles in the remaining cellars underneath the chapel of the former Palace of Coudenberg in Brussels, Belgium.

To prevent the deposition of lime bloom at the surface of the masonry and to achieve an acceptable colour match of the grout in harmony with the bricks of the Aula Magna, the effect of brick powder added to natural hydraulic lime was studied. The pozzolanic properties and colour match of several historic and modern powdered bricks were investigated. Surprisingly, ancient bricks do not seem to possess higher pozzolanic properties than the more modern ones, although it is supposed that they were fired at lower temperatures. Additional evidence for the pozzolanic reaction of the different brick powder materials was obtained from a simple visual observation of stored samples. After eight weeks all of the samples containing brick powders, fired at low and high temperatures, added to putty lime had hardened under water and were transformed into a remarkably tough material. These results are important, as modern bricks are readily available in large quantities and different colours, which are hence in favour of being used instead of historical material from the site.

For the repair of the ceramic floor tiles different mortars were investigated with mixtures containing talcum, stone or brick powder, pigments, and chalk added to an epoxy binder. The mortars were tested in the laboratory and in situ for their workability and resemblance with the historic floor tiles. The finished mortars showed excellent aesthetic properties with the tiles in situ and good properties to prevent further loss due to human interaction.     

Investigation of lime mortars and plasters from archaeological excavations in Hippos (Israel) using Electron Paramagnetic Resonance

This study presents the preliminary results of investigation of the lime mortars and plasters from archaeological excavations in Hippos (Israel), using Electron Paramagnetic Resonance (EPR) spectroscopy. The research was conducted in order to characterize the building material and its reaction to ionizing radiation. The ancient settlement Hippos, situated on the east shore of the Sea of Galilee, functioned from the 3^rd cent. BC until it was destroyed by the earthquake in 749 AD. Lime mortars and plasters show carbonate and locally gypsum character of binder and different kind of aggregate. Samples were γ-irradiated and measured using X-band EPR spectrometer. Computer Resolution Enhancement Method was applied to the complex spectra. Some of the γ-induced EPR signals were attributed to CO₂ ^? and CO₃ ^3? paramagnetic centres. Exponential growth of the dose response curve above 1 kGy and saturation for doses above 20 kGy was observed. For doses lower than 1 kGy the dose response curve has a linear character. The presence of γ-sensitive carbonate paramagnetic centres could indicate that, after further studies, well-chosen samples of mortars and plasters might be suitable for EPR dating, assuming the centres have been sufficiently bleached during the manufacturing process.     

A Multidisciplinary Approach to the Study of Archaeological Mortars from the Town of Ammaia in the Roman Province of Lusitania (Portugal)

The Roman town of Ammaia (in Marvão Region) is considered one of the most important recent findings of the Roman presence in Portuguese territory. It was settled in Republican times and abandoned in the seventh century. In this research, 17 masonry mortars and renders from the West Tower (South Gate), the residential area near the West Tower, the macellum, the peristylium, the public bath building, the podium of the temple and the portico of the forum were analysed. The methodology of chemical, mineralogical and microstructural characterization has involved several complementary techniques, including stereomicroscopy, X‐ray diffraction, thermal analysis and scanning electron microscopy coupled with energy‐dispersive X‐ray spectroscopy. The results indicate that the mortars from the beginning of the town's edification were mainly composed of soil (clays). Later, during the main Roman building period, mortars were composed using a calcitic binder and the mortar composition varied according to their use and function. The samples from a period subsequent to the Roman occupation are based on a dolomitic binder. From the present study, relevant information has been acquired about the technological evolution of Roman construction in Ammaia, the historical context of the archaeological structures and guidelines for the conservation and restoration of mortars.     

The ancient pozzolanic mortars and concretes of <Emphasis Type="Italic">Heliocaminus</Emphasis> baths in Hadrian’s Villa (Tivoli,Italy)

The aim of this work is the physical and mineralogical-petrographic characterization of the mortars from the Baths with Heliocaminus, a special and unique architectural building in the complex of the Hadrian’s Villa in Tivoli. Thirty samples were investigated for composition and physical properties (density, porosity, water absorption, mechanical strength, particle size distribution of aggregate, etc.), representative of eight mortar groups: cubilia bedding mortar, brick bedding mortars, floor-coating and wall-coating bedding mortars, floor (rudus) and wall conglomerates (trullisatio), vault concretes, and lime plasters (arriccio). Physical parameters, together with the microscopic analysis and binder/aggregate ratio determined in three ways using image analysis (on thin sections and on specimens) and weight-data from dissolution of binder, have shown an interesting relationship between the physical-compositional characteristics and the function of mortars within the structure of the Heliocaminus baths. To identify the minerals and the reactant phases between binder and aggregate, as well as the hydraulic degree, selected samples were analyzed with x-ray powder diffraction, thermogravimetry, and differential scanning calorimetry techniques. The obtained results provide a close relation between pozzolanic characteristics and physical-mechanical properties of the mortars (i.e., punching strength index).     

Comparison of Original and Modern Mortars at the Herculaneum Archaeological Site

ABSTRACT

This paper aims to evaluate mineralogical, elemental, and thermal differences among original Roman joint mortars and those used in twentieth-century restoration campaigns taken from different areas at the Herculaneum archaeological site. The purpose is to improve the compatibility of restoration mortars. Roman and modern mortars were studied with petrography, thermal analysis and x-ray fluorescence investigations. The results indicate significant differences between the Roman and modern mortars which could facilitate the degradation process. Roman mortars, in particular, were composed of a coarser aggregate which was present in a lower ratio with binder in comparison with modern mortars.     

Characterization of ancient building lime mortars of Anhui province,China: A multi-analytical approach

The characterization of lime mortars has become of primary importance in order to obtain information about the raw ingredients and building technology of ancient masonry structures. Five different samples from Anhui province, China, representing two types of lime mortar-based materials: joint mortars between the bricks of the city wall and lime mortar sealing a tomb coffin, were collected for analysis. Archaeological information about the samples was reported and studies into the microtextural features and mineralogical compositions of those mortars were performed via a multi-analytical approach. The joint lime mortars between the bricks of city walls, including Mingzhongdu city wall, Mingzhongdu Xihua gate foundation, Zhengyangguan city wall and She county city wall, were found to be aerial lime mortars. The lime mortar from Nanling Tieguai Song dynasty tomb was analysed and found to be a pozzolanic mortar consisting of lime, clay, sand and cocciopesto-like materials. The analytical results serve as a critical reference for the maintenance and restoration of ancient city walls in Anhui province, and as a starting point for searching for ancient Chinese pozzolanic mortars and technology for making those mortars.     

A Multidisciplinary Approach for the Archaeometric Study of Pozzolanic Aggregate in Roman Mortars: The Case of Villa dei Quintili (Rome,Italy)

This contribution focuses on the study of historical mortars from a Roman archaeological site known as Villa dei Quintili, a monumental villa located in the south‐eastern part of Rome (Italy). The study was carried out on 38 mortar samples, collected from several edifices within the complex. A multi‐analytical approach, including polarized optical microscopy, scanning electron microscopy coupled with energy‐dispersive system and laser ablation inductively coupled plasma mass spectrometry, was used to analyse the pozzolanic material used for the preparation of mortars. Data obtained on both major and trace elements were compared with the compositions of Pozzolana Rossa, Pozzolana Nera and Pozzolanella samples from the Alban Hills volcanic district, collected from a historic quarry nearby, as well as with literature data. The results of such a multidisciplinary approach allowed us to recognize the use of all three pozzolan types for the aggregate fraction of examined mortars from the Villa dei Quintili.     

ASSESSMENT OF THE BINDER IN HISTORICAL MORTARS BY VARIOUS TECHNIQUES

Three different historical mortars, one from the 18th–19th centuries and two from the 12th century, were crushed and sieved to give eight fractions between less than 0.063 mm and 4 mm for each sample. Each fraction was chemically analysed for the amount of calcium carbonate binder, using the reactions with HCl and EDTA and by means of atomic absorption spectroscopy. The samples were also characterized by X‐ray diffraction (XRD) and by low‐temperature nitrogen adsorption isotherms. The limitations and advantages of each of the various methodologies for the determination of the binder are discussed. Reactions with HCl and XRD were shown to be the methods that gave the more coherent results.     

ON STATISTICAL APPROACHES TO THE STUDY OF CERAMIC ARTEFACTS USING GEOCHEMICAL AND PETROGRAPHIC DATA*

The scientific analysis of ceramics often has the aim of identifying groups of similar artefacts. Much published work focuses on analysis of data derived from geochemical or mineralogical techniques. The former is more likely to be subjected to quantitative statistical analysis. This paper examines some approaches to the statistical analysis of data arising from both kinds of techniques, including ‘mixed‐mode’ methods where both types of data are incorporated into analysis. The approaches are illustrated using data derived from 88 Late Bronze Age transport jars from Kommos, Crete. Results suggest that the mixed‐mode approach can provide additional insight into the data.     

EVALUATING THE AGGREGATE SPATIAL STRUCTURE OF CANADIAN METROPOLITAN AREAS

Few attempts have been made to develop and test a conceptual framework for the comparative analysis of urban spatial structure and growth. This paper offers one aggregate approach as well as a series of empirical tests based on Canada's 27 largest urban areas. Six composite indices are introduced: population densities, rates of change, intraurban population redistribution, mobility rates, incidence of low-income populations, and degree of social polarization. Regression analyses reveal that differences among urban areas in spatial patterning and structural change are consistent with the hypothesized effects of city size, age, transport usage, social heterogeneity, production base, and physical setting. Yet immense regional and intraurban diversity remains. No single model of urban structure is sufficient to capture this diversity. On enregistre peu de tentatives pour mettre au point et tester un cadre conceptuel qui puisse servir à I'analyse comparative de structure spatiale et de croissance urbaine. Get article offre une approche g/oba/e ainsi qu'une série d'analyses empiriques basées sur les 27 territoires urbains canadiens les plus grande. Six indices composes servent aà l'analyse: densité de population et taux de changement de ces densités, redistribution et taux de mobilité de la population intra-urbaine, incidence de revenus faibles et importance de la polarisation sociale. Les analyses de régression démontrent que les différences dans l'arrangement des espaces et le changement des structures entre les zones urbaines sont en accord avec les effets supposés de taille urbaine, d'âge, d'utilisation du transport, d'hétérogénéité sociale, de base de production et de cadre physique. Cependant, une très grande diversité régionale et intraurbaine de-meure, II n'existe pas un seul modèle de structure urbaine capable d'englober cette diversité.     

Peculiarities of sedimentation conditions in the oxbow lakes of Dubysa River (Lithuania)

Abundant wood remains and buried trees have been found in the western part of Lithuania near Zakeli?kiai and Lyduv?nai on Dubysa River (a tributary of Nemunas River) where deposits are rich in organic remnants and buried soils. In Zakeli?kiai and Skiru?iai sections of Dubysa River oxbow sediments were investigated by various methods (dendrochronological, carbonate, granulometric, pollen and mollusc fauna analysis). In addition, these sections were dated using the radiocarbon method. Samples were collected from deposits of Dubysa River outcrops. The studied oxbow lakes have existed for more than 5 thousand years (from ca. 4300 BC to 1000 AD). During this period organic rich deposits with trees and branches were formed in the oxbow lake. This indicates that at the end of Atlantic, during Subboreal and in the early Subatlantic periods there was a forest growing that contained mainly oaks which were falling down into an oxbow lake and later were covered by sandy and silty deposits. The granulometry of alluvial deposits, as well as the mixture of medium-grained sand and silt show different stages of Dubysa River palaeochannel formation: riverbed and oxbow lakes. Three climate warming cycles were revealed according to carbonate analysis data in all investigated sections. The rheophile thermophilous Holocene age molluscs species Bithynia tentaculata L., Unio cf. crassus Philipsson, Pisidium amnicum (Müller), Theodoxus fluviatilis (Linnaeus) have been found. The pollen composition and sequences have been divided into five local pollen assemblage zones (LPAZ) and described according to pollen spectra in each zone. In this way it is possible restore palaeoclimatic coherent evolution, trends and cyclical change.     

Llanvirn-early Caradoc trilobite biofacies of western Hubei and Hunan,China

On the basis of representative collections made from seven measured sections in western Hubei and Hunan, four early Llanvirn and five late Llanvirn-early Caradoc trilobite biofacies are distinguished along a bathymetric gradient from shallow to deep outer shelf. The diversity and relative abundance of mesopelagic cyclopygids gradually increased southwards or seawards. According to the facies association exhibited in the region, the upper limit of living depth for different forms is inferred as follows: 1) more than 70 m (M. (Microparia)); 2) less than 100 m (M. (Quadratapyge), Pricyclopyge, Aspidaeglina); 3) at approximately 100 m (Cyclopyge); and 4) more than 100 m (Symphysops, Psilacella). Benthic forms were absent in the deep outer-shelf basin because of stagnant conditions. In shallower sites of the outer shelf, genera of nileids in the carbonate facies and raphiophorids in the clastic facies were relatively abundant, but some endemic forms, such as the asaphid Birmanites and remopleuridid Hexacopyge, became dominant during the late Llanvirn-early Caradoc. Rorringtoniids are mainly associated with deeper outer-shelf facies. Panderia is common in an early Llanvirn nileid fauna at Yichongqiao, Cili area, and may well indicate development of shelf carbonate buildups. A transgressive event is suggested by the sudden appearance of rich Cyclopyge in the early Caradoc at Jiuxi, Changde.     

Kinetic effect of carbonic anhydrase enzyme on the carbonation reaction of lime mortar

The effect of carbonic anhydrase enzyme on the precipitation kinetics and phase transformations of calcium carbonate, and on the strength development of lime mortars has been investigated with saturated lime solutions, lime pastes and lime mortars under atmospheric conditions. The results clearly show that carbonic anhydrase catalyzes the reaction between carbon dioxide and aqueous lime, and increases the rate of calcium carbonate crystallization, the yield of the carbonation reaction and mortar strength at early ages. This is most likely a kinetic effect associated with the increased rate of carbonate ions supply to the solution by the enzyme. In addition, this enzyme favors the formation of stable calcite and significantly modifies its morphology by developing new crystal faces. These results suggest a novel approach for accelerating the hardening of lime mortars using carbonic anhydrase enzyme, which may offer a potentially novel approach with significant benefits on the applications of lime mortars in architectural heritage conservation as well as in construction.     

OXYGEN AND CARBON ISOTOPE ANALYSIS OF HUMAN TOOTH ENAMEL FROM THE NEW KINGDOM SITE OF TOMBOS IN NUBIA

This study examines the feasibility of using oxygen isotope analysis of tooth carbonate to identify immigrants from the New Kingdom site of Tombos in Nubia (n = 30). In comparison with published data, the results (δ¹⁸O_ca,VSMOW = 31.4‰) imply a substantial presence of immigrants. However, further analysis of these data strongly suggests the need to consider hydrological and cultural factors such as the contribution of aquifer waters to the Nile, use of groundwater sources, and differences in handling and storage of water. The carbon isotope analysis, in conjunction with published ⁸⁷Sr/⁸⁶Sr data, provides additional support for the presence of immigrants at Tombos.