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Papers by Anna Addis

Journal of Cultural Heritage, 2019

Structural mortars constitute one of the most diffuse geomaterials, with stones and bricks, in an... more Structural mortars constitute one of the most diffuse geomaterials, with stones and bricks, in ancient monuments and architectural complexes, especially related to the Roman civilization, which pushed the binder technology to technical levels unsurpassed until post-industrial revolution times. The archaeometric study of mortars is an essential tool to extrapolate great amounts of information concerning supply of raw materials, technological skills of the ancient civilizations and, finally, relative and absolute chronologies of diachronic construction phases, both related to ancient and modern architectural modifications of the buildings. In this contribution, a novel approach for the quantitative mineralogical analysis of ancient mortars is proposed. The analytical process is based on the integrated application of quantitative phase analysis (QPA) of mineral components by means of the Rietveld method applied to X-ray powder diffraction (XRPD) data and multivariate statistical treatment of the obtained results by means of the principal component analysis. The methodology has been applied on a wide set of binding materials sampled from different structural elements of the Sarno Baths, a five-storey building located in the Pompeii archaeological site. The building is characterized by a marked complexity both in terms of structural layout and constructive techniques, being the result of several modifications in ancient times from the Late Republican age up to the Vesuvius eruption in 79 AD. Furthermore, several poorly documented restorations have been performed between the 19th century and the first half of the 20th century AD. In this perspective, a quantitative characterization of the employed mortars resulted useful not only to define ancient constructive technologies and relative chronologies, but also to discriminate between the original and restored parts of the building for the execution of adequate restoration procedures. The statistical clustering of the quantitative XRPD data clearly defined two ancient constructive phases and allowed a precise definition of the structural elements rebuilt in recent times. Furthermore, the obtained results have been cross-checked with additional analyses, namely XRD analyses on the separated binder fractions, petrographic analyses and scanning electron microscopy-energy-dispersive microanalyses. Such multi-analytical approach allowed the detailed characterization of the employed raw materials, of the pozzolanic reactions between binder and aggregate and of the textural and microstructural characteristics of the mortars. The data interpretation yielded interesting insights both on the advanced optimization of mix designs of binding materials in Roman times, to improve the structural properties of the architectural elements according to their functions, and on the formulation of the restoration products during the historic excavations in Pompeii.

Radiocarbon, 2019

In order to radiocarbon (14C) date a building, several components of the mortar could be used, ... more In order to radiocarbon (14C) date a building, several components of the
mortar could be used, such as the mortar binder, the lime lumps, the charcoal particles and shell fragments eventually present among the aggregates. In particular, the mortar binder requires a purification treatment in order to separate it from other sources of carbon, which could change the 14C signature of the binder invalidating the dating process. Here, we present the application of the Cryo2Sonic method to 14C dating of the ancient building structures unearthed during excavation at the Padua Cathedral complex. The dated samples were pretreated by using Cryo2Sonic method and the improved Cryo2Sonic version 2.0, recently developed by introducing additional steps such as centrifugation of the mortar suspension and gravimetric sedimentation of the binder fractions. The Cryo2Sonic version 2.0 relies heavily on the characterization of the mortar and of the purified binder fractions, allowing the isolation of a reliable 14C datable mortar fraction. Through this new method, the 14C dating of different ancient structures excavated next to he Padua Cathedral allow to identify the first religious complex of the city of Padua (3rd–4th centuries AD).

A new binder purification protocol for radiocarbon dating of mortars has been developed from Marz... more A new binder purification protocol for radiocarbon dating of mortars has been
developed from Marzaioli et al. [1] and tested on samples of several historic religious
Italian buildings, with the aim of verifying the efficiency and reliability of the protocol. The
new protocol is based on the gravimetric sedimentation of binder particles separated from
the other mortar components according to their grain sizes. The analyzed mortars come
from the baptistery of Padova, the church of Lomello (Pavia), and the church and
settlement of Santa Maria di Torba, near Castelseprio (Varese). The radiocarbon dating of
the purified binders are compared with the archaeological records and with those resulting
from 14C measurements of carbon fragments extracted from the same samples. The
resulting dates show an excellent correspondence between radiocarbon dates and the
archaeological evidence.

The paper reports the results of a research project aimed at the characterization of the floor be... more The paper reports the results of a research project aimed at the characterization of the floor
bedding mortars of two Roman houses in Aquileia (north-eastern Italy), the Domus delle
Bestie Ferite and the Domus di Tito Macro. Seventy floor bedding mortars of the two domus
were selected and almost half were fully minero-petrographically characterized by means of
optical microscopy operated in transmitted light (OM-TL), X-ray powder diffraction analyses
coupled with quantitative phase analysis by means of the Rietveld method (XRPD-QPA) and
scanning electron microscopy with EDS microanalysis (SEM–EDS). The results indicate an
evolution of the mortar preparation techniques over time in the mosaic of both houses. The
materials are compared to the traditional Roman recipes for specific construction techniques.

The increasing demand for sustainable low-strength binding materials, to be used in the conservat... more The increasing demand for sustainable low-strength binding materials, to be used in the conservation of historic masonry structures and as a eco-friendly architectural material, has stimulated the investigation of the properties and performance of clay-based mortars. The study and parameteriza-tion of traditional earthen architecture is an increasingly promising research field, in order to assess the sustainability, the durability and the long-term performance of the masonry structures. Several examples of the use of lime-stabilized clay-based binders may be found in the traditional and historic architecture of the Western cultures, besides its widespread use in the traditional architecture of developing countries. In this contribution, three case studies of historic and archaeological Italian masonry structures employing mixtures of lime and soil as binding materials are reported, built in a wide timespan ranging between the VI and the XIII Century A.D.. The study is focused on the chemical and mineralogical characterization of the raw materials employed and in the interpretation of their reaction processes, especially the degree of pozzolanic reaction between lime and the reactive component of the clay fraction. The excellent textural characteristics and ultimate performance of several of the analyzed materials clearly demonstrated their potential, even when employed in temperate climates, opening new perspectives in the field of eco-sustainable binders.

The smelting copper slags from the archaeological sites of Transacqua and Segonzano in Trentino (... more The smelting copper slags from the archaeological sites of Transacqua and Segonzano in Trentino (Italy) were fully analysed to study the extraction of copper from copper and iron sulphide minerals that were carried out in the southeastern Alps during the Late Bronze Age. A combined approach involving physical, chemical, mineralogical and petrographic analyses was applied on over 130 copper slags from Transacqua and Segonzano. Three different types of slags were distinguished from the mineralogical and chemical points of view, differing in the size and relative amount of the unreacted sulphides and matte, the size of metallic copper prills, the ratio between unreacted quartz and newly formed silicate phases and viscosity. By combining all the observations, it is suggested that the three types of slags are the product of a Cu-smelting process formed by three main operations: slagging, matting and refining, which were standardised in the southeast Alps between the fourteenth and the eleventh century BC.

The present paper attempts to clarify the level of metallurgical knowledge achieved at the end of... more The present paper attempts to clarify the level of metallurgical knowledge achieved at the end of the Bronze Age in the Luserna copper smelting site, located in the Trentino area, a region well known for the number of protohistoric copper smelting sites. Over eighty slags samples of Luserna were investigated in order to understand: 1) the technological development of the smelting processes performed, 2) the possible use of different working-steps in the metal production process and the copper extraction efficiency, 3) the ore source of the smelted minerals. For these purposes a multi-analytical approach has been applied, involving minero-petrographic analyses and lead isotopes analyses.

The ‘Porta del Paradiso’ by Lorenzo Ghiberti, also known as the ‘Gates of Paradise’, will soon be... more The ‘Porta del Paradiso’ by Lorenzo Ghiberti, also known as the ‘Gates of Paradise’, will soon be unveiled to the public after undergoing lengthy conservation. This project is at the stage where it is necessary to define environmental criteria for the long-term display of the doors. In this paper, three possible methodologies for display of the doors are considered: a showcase purged with nitrogen; a showcase with low, controlled relative humidity; an open showcase with a controlled microclimate. Galvanic sensors were used inside the cases to continuously monitor the macrocouple current of the doors and establish which case provided the most stable environment for display. Results to date indicate that the showcase with low, controlled humidity may offer the best solution for long-term display of the doors.

In the Late Bronze Age, the extractive metallurgy of copper in north-eastern Italy achieved a pe... more In the Late Bronze Age, the extractive metallurgy of copper in north-eastern Italy achieved a
peak of technological efficiency and mass production, as evidenced by the substantial number
of metallurgical sites and the large volume of slags resulting from smelting activities. In order
to define the technological features of the Late Bronze Age metallurgical process, more than
20 slags from the smelting site of Luserna (Trentino, Italy) were fully analysed by means of
optical microscopy, X-ray powder diffraction, X-ray fluorescence spectrometry and scanning
electron microscopy. Three different slag types were identified based on mineralogical and
chemico-physical parameters, each being interpreted as the product of distinct metallurgical
steps. A Cu-smelting model is proposed accordingly.

The University of Padova has developed a geochemical database for the Alpine copper mines which c... more The University of Padova has developed a geochemical database for the Alpine copper mines which contains lead isotope data for most of the copper deposits in the Western Alps and Italian Eastern Alps, besides a number of other
geochemical tracers for selected deposits. The database fills an existing gap in available reference data and provides information for the geochemical interpretation of
the mineral deposits. It is of course also an important reference for archaeometric purposes, to provenance the mineral source of slags and metal objects. Several Alpine
copper deposits may now be successfully discriminated from those of other European and Mediterranean mining areas. The results obtained on a number of Copper Age and Bronze Age metal objects are presented. A few objects made with copper ores of South-East Alpine origin have been positively identified for the first time, though the data also indicate a wide circulation of copper metal possibly originating from ore
sources outside the Alps.

Conference Presentations by Anna Addis

J. De Laine, S. Camporeale, A. Pizzo (eds.), Proceeding of the 5th International Workshop on the Archaeology of Roman Construction. Arquelogía de la Construcción V. Man-made materials, engineering and infrastructure (Oxford, April 11-12, 2015), Merida, pp. 29-44.

Since ancient time, mortars have been used in order to bind masonry elements, to provide a level ... more Since ancient time, mortars have been used in order to bind masonry elements, to provide a level or smooth finish and to protect against weathering. Generally, a mortar is composed by a binder and aggregates. In the case of areal mortars, the binder is formed by heating limestone, a sedimentary rock mostly composed by calcite (CaCO 3 ). This process -called calcinationproduces quicklime (CaO) that is hydrated to obtain a lime putty formed by Ca(OH) 2 . The plastic lime putty is mixed with aggregates and placed in the wall. The hardening of the lime mortars occurs through the absorption of atmospheric CO 2 by the

39th International Symposium on Archaeometry: “50 years of ISA” Leuven 28 May – 1 June 2012 Abst... more 39th International Symposium on Archaeometry: “50 years of ISA”
Leuven 28 May – 1 June 2012

Abstract: The Recent and Late Bronze Age were periods of marked copper extraction activities in the Eastern Alps. Several furnaces and countless sites are known with abundant smelting slags of various type, including the Plattenschlake of well-defined composition and morphology (Anguilano et al. 2002, Weisgerber and Goldenberg 2004, Cierny 2008). The reconstruction of the Late Bronze Age smelting process are still debated, especially concerning the number and nature of the different high temperature working-steps employed in the process.
The detailed investigation of the copper slags found in several Eastern Italian Alps LBA sites suggest that the smelting process was performed in at least three standardised steps related to different levels of copper extraction efficiency (Addis et al., 2011). To the purpose of verifying the working steps assumed on the basis of the analyses of the archaeometallurgical slags, two seasons of copper smelting experiments were performed in the Summer of 2010 and 2011.
The first session of experiments principally aimed to explore the effect of different roasting cycles on the process. A number of twenty roasting experiments starting from three different types of commercial chalcopyrite were carried out using different strategies: charge roasting in crucibles heated in a furnace, and a open air roasting on piles of wood. X-Ray powder diffraction analyses on the starting materials and on the roasted products were performed at different stages during the process, which was repeated several times. These experiments allowed to select the most suitable charge to be used for subsequent smelting, to understand the efficiency of roasting strategies, and to assess the degree of transformation in the ores.
Several smelting experiments were performed using a charge of roasted/unroasted chalcopyrite plus quartz, inserted in crucibles within a furnace heated by artificial air source and coal. The mineralogical associations and the copper enrichment of the matte obtained during the trasformations were measured. These analyses allowed stoichiometric optimization of the chalcopyrite/quartz ratio in the charge.
The last experimental session was devoted to produce a highly copper-enriched matte from the optimized charge, and to understand the latter steps of the process including final copper extraction and formation of Plattenschlake-like slags.
Based on the results of the experiments and in agreement with the observed features of the archaeological slags, a working 3-step process is proposed as the basic scheme for LBA copper extraction activity: (1) repeated roasting of the charge, (2) mass production of copper-enriched matte with formation of coarse and massive slags, (3) re-processing of the matte for the extraction of copper, with multiple production of flat slags.

ADDIS, A., ANGELINI, I., ARTIOLI, G.,2011. Final Bronze Age copper slags from Luserna (Trentino, Italy). Atti VII Congresso Nazionale di Archeometria, 2012, submitted.

ANGUILANO, L., ANGELINI, I., ARTIOLI, G., MORONI, M., BAUMGARTEN, B., OBERRAUCH, H., 2002. Smelting slags from Copper and Bronze Age archaeological sites in Trentino and Alto Adige. In: D’AMICO, C. (Eds.), Atti II Congresso Nazionale di Archeometria. Bologna 29 Gennaio-1 Febbraio 2002, Pàtron Editore, Bologna, 627-638.

CIERNY, J., 2008. Prähistorische Kupferproduktion in den südlichen Alpen – Region Trentino Orientale. Der Anschnitt, Beiheft 22, Bergbau-Museum, Bochum.

WEISGERBER, G., GOLDENBERG, G. 2004. Alpenkupfer – Rame delle Alpi. Der Anschnitt, Beiheft 17, Bergbau-Museu,m Bochum.

THE HISTORICAL METALLURGY SOCIETY 50th Anniversary Conference & AGM June 2013 London 14th-16th J... more THE HISTORICAL METALLURGY SOCIETY 50th Anniversary Conference & AGM June 2013
London 14th-16th June 2013

Abstract:
At the end of the second millennium BC the extractive metallurgy of copper in North-Eastern Italy achieved a peak of technological efficiency and mass production, as evidenced by the large number of metallurgical sites and the total amount of slags resulting from smelting activities. Though several smelting processes have been proposed, an agreed interpretation of the whole process is lacking.
Based on a collaboration with the Archaeological Heritage Office of the Autonomous Province of Trento and thanks to their recent excavations (directed by Dr. F. Nicolis and Dr. P. Bellintani, with the collaboration of E. Silvestri), over 70 slags from the Luserna, Transacqua and Segonzano sites (Trentino, Italy) have been characterized by means of OM, XRPD, XRF and SEM-EDS. A few metallurgical smelting experiments were carried out in order to explore both the slagging and the matting processes.
Three different types of archaeological slags have been distinguished from the mineralogical and chemical points of view: the two well-known Alpine LBA “coarse” and “flat” slag types, and a new intermediate type of slag here defined as “massive”. The three slag groups differ in the size and relative amount of the unreacted sulphides, the highly Cu-enriched matte, and the metallic copper. The ratio between the restitic quartz and the newly formed fayalite and magnetite is also a distinctive parameter, possibly related to the maximum temperature involved in each step.
It is proposed that the three types of slags are related to three distinct metallurgical steps: 1) the coarse slags are the product of the initial roasting/slagging operations, where a Cu-poor matte is produced, mainly of bornitic composition, 2) the massive slags are the result of the major matting process, where a Cu-rich matte (covellite-chalcocite composition) is produced, and 3) the thin flat slags are the product of the final refining process, formed directly at the surface of the raw molten metal.

Books by Anna Addis