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Over the past decade, we have witnessed an increase in the use of technology, through the creation of virtual itineraries and exhibitions, as a tool to guarantee and increase the usability of museums and more generally of artistic and historical works. In fact, it often happens that many works of art and artefacts of archaeological and cultural importance are not accessible to the public, either because they are kept in museum deposits or because they are difficult to access. In a context such as the current one, however, with an ongoing pandemic that forces most of the population to remain at home, the virtualization of museums, and historical and cultural heritage, becomes the main tool for exploring and enhancing culture. Among the various methodologies used for the creation of three-dimensional models, photogrammetry stands out for ease of use and low cost. This article analyses the use of photogrammetry in 3D modelling, focusing on pros and cons as a rapid, low-cost tool, which makes artworks virtually accessible to the public via museum websites and social network forums.

This paper focuses on the study of different Roman mortars (renders, finishing coats), used in the construction and restoration of the Forum Traiani thermal baths (Central Sardinia, Italy), a significant example of the Roman-style architecture in Sardinia. The archaeological site is located in a high hydrogeological risk area, due to the cyclical flooding of nearby Tirso river. Moreover, the presence of thermal saline (NaCl-bearing) water spring directly in contact with mortars and building stones, also contributed to structure degradation. An analytical approach, comprising mineralogical-petrographic characterization, physical analysis and particle-size distribution of aggregate, was used for mortars characterization. In addition, pXRD analysis on mortars defined the presence of alteration minerals while the thermal characterization (TGA) gave information about binder hydraulicity degree. Further μ-XRD-associated μ-Raman spectroscopy and μ-FTIR were utilized for pigments identification on frescos. Interesting results came from two wall stratigraphic series of mortars, highlighting construction stages, ancient restoring interventions and waterproofing methods. The main pigments used on red, yellow and black frescoes were red ochre, goethite and wood charcoal respectively.

The Church of Santa Maria del Regno, a key monument of Sardinian Romanesque period, was studied both from the historical point of view, and the chemical-physical features of construction materials ("basaltic" rocks), locally affected by alteration processes, mainly oxidation processes.

The Church of Santa Maria di Tergu, located in the Sardinia Northern coast, and built up during the Age of the Giudici, was studied both as concerns the historical context and the building materials' features (reddish volcanic stones and whitish limestones), their provenance, chemical-physical decay.

This paper presents the study of various Roman materials used in the construction of the Maritime Theatre, one of the main buildings in the Hadrian’s Villa complex, a designated UNESCO World Heritage Site located in Tivoli (Rome, Italy), dating to the first half of the II century A.D. The plaster layers (arriccio and intonachino) and overlying original Roman paintings that form the concave wall of the portico as well as some bedding mortars of the pyramidal stone elements (i.e. cubilia) of the circular masonry have been studied in particular. In addition, the acid volcanic rocks of the cubilia have been investigated, aiming to understand their state of alteration and geological origin. By mineralogical-petrographic microscopy (OM), diffractometry (XRPD), Raman spectroscopy, Point Load Tests (PLT), helium pycnometry, and particle size analysis, the composition and granulometric distribution of the aggregate, type and characteristics of the binder, and various physical-mechanical properties (density, porosity, water absorption, imbibition and saturation indices, mechanical resistance) of mortars and stones were defined. In addition, through digital image analysis of thin sections, the binder/aggregate ratio and some geometric characteristics of the aggregates (e.g. circularity) were determined. The research aims to improve the knowledge of the constructive technologies of the Maritime Theatre through the analysis of its materials.

The work aims to define the origin of the architectural stone elements worked by Romans and reused in the St. Saturno Basilica, between the late Antiquity and Romanesque periods. Thus, different rocks (marbles, various facies of limestones, volcanic rocks) used to construct the ancient building were sampled and analysed. All the different kinds of stones were sampled from the Basilica, taking precise reference to the various construction phases and structural changes of the monument occurred in the centuries. The sedimentary and volcanic lithologies belong to the local outcrops of Cagliari Miocenic geological formation (e.g. limestone) and to other volcanic outcrops of south Sardinia, respectively. By means of a multimethod archaeometric study (mineralogical-petrographic observations on thin sections and 18O vs 13C stable isotope ratio analysis), the provenance of classical marbles used for manufacturing Roman architectural elements (column shafts, bases, capitals, slabs, etc.) were defined, which are thought to come from extraregional sources. The results show that the marbles come mainly from Apuan Alps (Italy) and subordinately from Greek quarrying areas.

The stone used on the monuments, especially if they come from ancient times (e.g. medieval period), when exposed to the atmosphere, they are frequently affected by weathering and bio-deterioration processes. Thus, these latter produce various chemical and mineralogical transformations of substrate at the interface with the atmospheric agents as function of intrinsic compositional and physical characteristics of the material. Moreover, if there also are ancient treatments on the surface of geomaterials, the investigation field is further complicated. This research aims to analyse the surfaces of different volcanic lithology (basalts, andesite, pyroclastic rocks) used in the medieval Romanesque churches of Sardinia (XI-XIV cent.) having high historical-architectural and cultural relevance. By mineralogical and petrographic analysis (OM) and other different analytical methods (XRPD, colorimetry) the investigations addressed to define: i) petrographic features of volcanic rocks substrate; ii) chemical and mineralogical composition of coatings/crusts and any salt fanoand cryptoefflorescence; iii) compositional and microstratigraphic characterization of ancient treatments (i.e., Ca-oxalate films) on the surface of facades; iv) chromatic modifications of surface with respect to the substrate due to the alteration processes. The results show the incidence of several factors in the alteration process, as function of the occurred time, petrophysical features and composition of geomaterials, their position in the monument structure, exposition to the weathering processes, microclimatic characteristics, environmental conditions.

La necessità di esprimere un linguaggio comune e chiaro rende le Chiese romaniche un importante esempio del linguaggio architettonico europeo, esprimendo forme, equilibrio, elementi artistici, che si diffondono in tutto il mondo medievale collegando le questioni di fede e devozione alla struttura sociale attraverso specifiche espressioni architettoniche. Il linguaggio romanico ha assunto caratteristiche specifiche in tutta Europa, modificandosi per aspetti specifici del sito, spesso adeguando le sue linee guida principali a bisogni e materiali locali. In Sardegna, una delle principali ed antiche isole del Mar Mediterraneo, l'introduzione dell'architettura romanica ha trovato la presenza sul territorio sardo di diverse evidenze archeologiche ed architettoniche di insediamenti precedenti e di una risorsa geologica (da utilizzarsi per l'approvvigionamento dei materiali costruttivi) molto variegata, a tratti assai diversa dalle aree in cui questo linguaggio architettonico si era originariamente sviluppato. Pertanto, il libro si propone di focalizzare i rapporti fra il monumento architettonico e il territorio di riferimento, nella prospettiva storica come in quella attuale, attraverso lo studio di casi esemplari rappresentati dalle chiese romaniche edificate in Sardegna nell'età giudicale (dal XI° al XIII° secolo). Scopo generale è stata l'elaborazione ed applicazione di una metodologia di studio dei manufatti architettonici che sappia integrare l'apporto di discipline tradizionalmente d'ambito umanistico (archivistica, epigrafi a, storia dell'architettura, storia dell'arte) con altre di ambito scientifico (geologia, mineralogia, petrografia, petrofisica, geochimica), insieme alle tecnologie di rilievo laser-scan, volta a comprendere su quali connessioni territoriali si fondava la relazione fra la chiesa romanica e il paesaggio circostante. Ciò attraverso un confronto diretto dei dati minero-petrografici-geochimici dei materiali costruttivi; l'attività di ricognizione delle cave di estrazione della pietra consente infatti di precisare quali erano durante l'età giudicale i fattori che sovrintendevano la scelta dei materiali (e quindi delle cave) e come e quanto questi fattori si correlassero con le esigenze di tipo politico, estetico, o, più semplicemente con quelle di tipo pratico.

The research discusses a part of the modern fortification of Cagliari built since the XVI centuries: the bastion of Santa Croce. The Cagliari fortifications show the designs of "modern" technologies that around the middle of the XV century in Europe replaced the medieval walls, with several changes to the structures (i.e.: lowering of buildings, replacement of quadrangular medieval towers with lesser height cylindrical, increase of the thickness of the walls through the creation of embankments, etc.). For the boundary walls of Santa Croce, built between 1568 and 1578 and completed with additional outworks in the XVIII century, were used local carbonate rocks of Cagliari's geological Miocene formation. The main represented lithologies used in the wall structure are the Pietra Cantone, Tramezzario and Pietra Forte limestones. These rocks are also used in the La Concezione and San Guglielmo structure walls. Subordinately, in the bastion of Santa Croce (as well as in the curtain of San Guglielmo) there are the occasionally presence of volcanic ashlars belong to Asuni area (central-south Sardinia). These volcanic ashlars are used as materials for the recent consolidation and restructuring of the fortifications of Cagliari, implemented in the century before. Primarily, the study analyzes the relationships between the ancient construction technologies and the use of stone in these building walls. Secondarily, it analyzes the decay of geomaterials to define the chemical and physical processes in progress in the monument, and to identify how to intervene in the restore works, in order to consolidate the material where there is obvious static-structural criticality.

Nell’ambito di un ampio progetto di ricerca sui materiali impiegati nell’edilizia del centro storico di Siena (Italia) è stato intrapreso uno studio mineralogico-petrografico sulle malte di allettamento provenienti dalle fortificazioni progettate da Baldassarre Peruzzi nella prima metà del XVI secolo e un confronto con malte impiegate in settori della cerchia muraria risalenti ad epoche precedenti (XIV e XV secolo). Le indagini preliminari hanno consentito di verificare l’impiego di malte di diversa tipología nelle fortificazioni peruzziane rispetto a quelle antecedenti, con uso di calci ad elevato indice di idraulicità e maggiore cura nella selezione e nel trattamento degli aggregati. Queste evidenze suggeriscono una scelta deliberata di nuovi materiali, più avanzati sul piano tecnologico, nel contesto di importanti interventi di potenziamento delle difese cittadine attuati agli inizi del Cinquecento.