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Today, the need to dispose of a huge amount of ceramic industrial waste represents an important problem for production plants. Contextually, it is increasingly difficult to retrieve new mineral resources for the realization of building materials. Reusing ceramic industrial waste as precursors for building blocks/binders, exploiting their aluminosilicate composition for an alkaline activation process, could solve the problem. This chemical process facilitates the consolidation of new binders/blocks without thermal treatments and with less CO2 emissions if compared with traditional cements/ceramics. The alkali-activated materials (AAMs) are today thought as the materials of the future, eco-sustainable and technically advanced. In this study, six different kind of industrial ceramic waste are compared in their chemical and mineralogical composition, together with their thermal behaviour, reactivity in an alkaline environment and surface area characteristics, with the aim of converting them from waste into new resources. Preliminary tests of AAM synthesis by using 80%–100% of ceramic waste as a precursor show promising results. Workability, porosity and mechanical strengths in particular are measured, showing as, notwithstanding the presence of carbonate components, consolidated materials are obtained, with similar results. The main factors which affect the characteristics of the synthetized AAMs are the precursors’ granulometry, curing temperature and the proportions of the activating solutions.

Due to the surprising lack of knowledge concerning raw materials and production technology employed to make mosaics after the twelfth century, an archaeometric investigation was carried out on the materials constituting the mosaic decoration of the South aisle wall of Monreale Cathedral (Italy), taking advantage of a conservation intervention. In this work, fallen coloured or gilded glass tesserae to be repositioned were studied by means of a combination of a molecular technique (Raman spectroscopy) and an elemental one (portable X-ray Fluorescence, pXRF); also, efflorescences affecting the general conservation state and samples of the respective bedding mortar were analysed with the former technique and with X-ray diffraction (XRD). The raw materials used and, consequently, the different compositions characterizing gilded vs. coloured glass tesserae were highlighted with the vibrational spectroscopy; chromophores and trace elements were detected by pXRF. This complementary approach allowed to disclose clues about glass-manufacturing technique and raw materials. The nature of the salts was also ascertained through Raman spectroscopy and XRD, for the benefit of the conservation procedure, and connected to the mortars’ composition.

This paper presents the results obtained from the thermal analysis of a set of geomaterials (clays, pyroclastic materials, and industrial recycled materials) to be used as raw materials for the synthesis of geopolymers, specifically designed for the conservation of Cultural Heritage (CH) buildings, particularly in seismic hazard zones such as Sicily. X-ray diffraction and gas volumetric analysis (calcimetry) were applied to this set of raw materials in order to characterize the materials from the chemical and structural point of view. Thermogravimetric analysis (TG), TG coupled to Fourier transform infrared spectroscopy (TG-FTIR), and differential scanning calorimetry were used to characterize their thermal behavior. The statistical treatment of the thermogravimetric data by principal component analysis and hierarchical clustering analysis highlights the direct relation between the thermal data and the material composition that will be exploited for the selection of the best materials to obtain geopolymers specifically designed for the conservation of CH buildings.

Recently, attention has been claimed to the conservation- restoration of Cultural Heritage. This paper is focused on the creation of thematic maps which incorporate attribute data from the building materials to the type of stone damage. This approach would be a contribution for monitoring the knowledge of stone deterioration and facilitating the information collection in the optic of the most appropriate sustainable monument preservation measures. For this purpose, in the framework of the Italian National Research Program “Advanced Green Materials for Cultural Heritage”, eight historical buildings located in the Catania city center (Sicily) have been selected and the geodatabase AGM (Advanced Green Materials) has been created to archive a lot of data obtained in this study. The final pilot system allows to: i) import and export different graphical and alphanumerical data more than one coordinate systems (cadastral data); ii) generate new thematic maps by querying on the database (map of alteration processes in relation to the type and exposure of the elevation); iii) relate to each other different physical or logical data (processes of natural and anthropogenic environmental pollution); iv) define, in a parametrical manner, queries and entities properties directly from the user interface (extract mathematical and analytical models of the interrogated processes). SfM (Structure from Motion) survey techniques and automatic digital photogrammetry systems have been used to measure the geometries of the architectural elements, and a database-GIS (Geographic Information System) has been planned in order to storage and process the associated attribute data of both building materials and decay forms.The result was the development of a powerful tool for managing all the historical buildings information.

Negli ultimi decenni, lo studio dei ritrovamenti di ceramica di epoca medievale o post-medievale in Sicilia si è avvalso dell'apporto delle indagini archeometriche, condotte su frammenti provenienti da diversi siti, prevalentemente da Caltagirone. In questo lavoro, con l'obiettivo di approfondire le tecnologie di produzione impiegate, dodici frammenti di ceramica smaltata datati fra il XV e il XVI secolo e provenienti da Caltagirone, Buscemi, Scicli e Modica sono stati sottoposti ad osservazione microscopica e analisi chimico-mineralogica, con un particolare focus sugli smalti di colore blu.

Polychrome painted plasters from a suburban villa of Imperial epoch were recovered during the 1930s, and are currently exhibited in the galleries underneath the St. John in Lateran Church, Rome. As wall paintings from the Rome area are a rare find, and as the fragments were never subjected to conservation treatments, it was chosen to non-invasively characterize 113 coloured areas, representative of colours and decorative systems. The chemical and mineralogical information collected from this measurement campaign were interpreted in the light of archaeological context (i.e. the high status of the family who owned the villa, the different renovation works that affected it, the identification of decorative systems linked to such works), as well as of published data from contemporary wall paintings in the Rome area. A multi-analytical, non-destructive characterization of the painted surfaces was carried out in situ by means of portable Raman spectroscopy (pRS) and X-ray fluorescence (pXRF), in the framework of a wider project concerning the study of raw materials and paintings of archaeological interest. The combination of pXRF and pRS allowed to characterize the whole palette, as well as to discriminate among different pigments sharing the same key element, and to identify degradation issues. In this context, the use of principal component analysis gave an important contribution to the interpretation of data ant to the individuation and characterization of pigments such as ochres, green earths, lead based pigments, Egyptian blue, cinnabar, Tyrian purple. Calcium and magnesium carbonates are present, as expected, in the plaster, and are often associated with their sulphates and nitrates, and Ca-oxalates indicating degradation. Lead white and bone white have been used. Some peculiar yellow pigments have been identified, such as realgar/pararealgar and Naples’ yellow, in addition to ochres. Hematite, minium and cinnabar were all identified, alone or in mixtures. The presence of the precious dye Tyrian purple is very likely, but could not be confirmed univocally. Green earths and complex mixtures of iron and copper compounds were detected. Egyptian blue was used, highlighting different production processes for this artificial glassy material. For the blacks, we hypothesize the use of carbon-based pigments. The obtained data confirms the general palette used by Roman painters, and sheds new light on the materials used in the Lateran area across two centuries, including their provenance and manufacturing. It appears that different earths and ochres were used diachronically, and that the owners could afford very expensive pigments, such as cinnabar and Tyrian purple.

Nowadays mineralogical and petrographic sciences represent important resources for the understanding of natural and cultural heritage. Indeed, the implication in economic and social scenario, from the exploitation of geo-resources to the natural stone application in architecture, involves the whole society. In this context, scientific museums are called to enhance society awareness about the importance of minerals and rocks, while facilitating their understanding. It is well-known that the majority of the population is still left out from the museum fruition, usually because of problems of cultural accessibility. In order to find a solution, the Museum of Mineralogy, Petrography and Volcanology of the University of Catania implemented a new communication system based on the visitor’s personal experience. The idea is to give to all users, regardless of their educational level, the possibility to learn by playing. The collaboration among geologists, conservators and computer scientists led to the implementation of a web application called I-PETER: Interactive Platform to Experience Tours and Education on the Rocks. The application, interacting with a database, offers to the public two different modes of exploring the museum’s collections. The visitor can decide to observe the rocks or minerals from the sample exposed to the internal structure and then explore their external application on monuments, or he/she can choose to make a tour in the interactive map, focusing on a particular monument and from there make the virtual reverse path from the macro to the micro scale. Furthermore, thanks to the effort made to construct the knowledge base at the base of I-PETER web app, a labelled dataset of images of rocks and minerals can be easily released for future petrological investigations based on machine learning. Thanks to this pilot project, the museum’s scientific knowledge can promote cultural tourism by making it more accessible to a wide public, as well as support scientific research on petrography and mineralogy.

Zeolites are present in numerous outcrops of volcanites of different ages in Sicily (Italy). Some of these outcrops are important because they constitute the ideal genesis conditions of some of these minerals, which represent geological indicators of chemical and geothermal gradients involved during their formation. For this purpose, a group of zeolites coming from areas of the Ionian coast and Palagonia village (Eastern Sicily) was investigated by means of Raman spectroscopy. In the geological record, these areas have been influenced by intense volcanic events that produced mineralization of hydrothermal origin. Sicilian zeolite samples were analysed in situ using different mobile Raman apparatus, directly on the outcrops of Aci Castello and the nearby Lachea Island, or in local collections where they are preserved. Some of these samples have been then analysed using laboratory micro-Raman to compare the results and identify the zeolite types. The strength and weakness points of each instrument have been highlighted. Often, the Raman spectra of zeolites are affected by broad fluorescence, making them of difficult interpretation. However, satisfying results were obtained with portable devices, whose identifications were confirmed by micro-Raman, discerning zeolites of different groups, such as analcime, chabazite, natrolite and phillipsite. The use of portable instruments has demonstrated the possibility to obtain identification of zeolites and related minerals both on site and in the laboratory, whose results match with the geological setting of the considered areas.

Archaic Roman painted antefixes, architectural slabs and louteria from the Palatine Hill in Rome, Italy, were studied by non-destructive and micro-destructive methods: Portable X-ray fluorescence (XRF), micro-Raman spectroscopy, optical microscopy, scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) and X-ray diffraction (XRD). The investigation enabled the characterization of raw materials and ceramic technology, providing insights on provenance. In fact, similarities were recognized with terracottas from the neighbouring Etruscan Veii. The analysis of pictorial layers revealed the use of Fe- and Mn-based pigments, as well as the identification of more precious pigments on worthy pieces. The research intended to support the archaeological discussion about the frame of the nascent city of Rome, also in relation to the coeval Etruscan culture.

Geopolymers, synthesized starting from aluminosilicate precursors activated with alkaline solutions, constitute a class of materials of high interest as potential substitutes of traditional, cementitious, binders. Infrared spectroscopy is one of the routine analytical techniques employed to study these materials and to verify the occurrence of geopolymerization; on the other hand, its portable version working in diffuse reflection is not enough exploited for their characterization. The aim of this work is therefore to assess the potentiality of Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) in the study of geopolymers. The combination of this technique with Principal Components Analysis (PCA) statistical treatment was used to search for criteria able to discriminate the successful products from those which require a correction in their formulation. Mainly, two groups of geopolymers were studied, based respectively on clay sediments and ceramic waste precursors, in the latter case with the possible addition of metakaolin. These samples were studied both after maturation, comprising several variables in their mix-design and curing, and during the first hours of solidification of the slurry. The results allowed to identify the best formulations within the analyzed groups. Besides, the extension of this study to a wider selection of geopolymers, such as the pumice-, volcanic paleo-soil- and/or metakaolin-based ones, already studied with other techniques, further confirmed the efficacy of DRIFT spectroscopy in the identification of the geopolymerization reaction.

Fragments and micro-fragments of painted plasters from the Sphinx Room, recently discovered in the Domus Aurea Esquiline wing (Rome, Italy), were studied. They were respectively taken from the debris in the vicinity of the walls and from already damaged edges of the decorated walls. A previous study, mainly based on non-destructive and non-invasive investigations, proved effective in giving a general overview of the employed palette, allowing the comparison with paintings from the same palace and other coeval contexts, and also providing some preliminary hints concerning the pictorial technique. Nevertheless, some issues remained unsolved, concerning the pigment mixtures (e.g., lead-/iron-based yellow to red colors, copper-/iron-based green/greyish areas), and the a fresco/a secco painting technique debate. Therefore, cross sections of the above-mentioned fragments were observed by means of Optical (OM) and Scanning Electron (SEM) Microscopy and analyzed with micro-Raman spectroscopy and Energy Dispersive X-Ray Spectroscopy (EDS), with the aims of: studying the paint layer composition through point analysis and mapping of the elemental distribution, comparing these in relation to what was observed with previously reported non-destructive analyses, studying the stratigraphy of the painted plaster, focusing on the contact between the plaster and the paint.

So far unexplored, the introduction and the spread of the Roman thermal buildings in the prima provincia (Sicily) are widely debated in the current archeological studies. Mainly due to the lack of systematic excavations and intensively technological studies, the assessment of thermae in the Hellenistic-Roman Sicily has been thus far interpreted as a new social and architectural experience. However, a more careful archeological investigation would suggest a gradual transformation of the architectural landscape from the purely Greek bath tradition to the canonical thermae types. The aim of this paper is therefore to study the classical hot bath culture and, in particular, the transition from Greek to Roman architectural models (from βαλανeῖα to thermae) by applying an archaeometric approach on brick and tile samples from three Sicilian archaeological sites - Solunto, Taormina, Tindari - recently proved to be among the first towns in Sicily in which Roman thermae were established in the Early Empire. Petrographic, mineralogical (XRD), micromorphological (SEM) and geochemical (XRF) analyses has been performed on a selection of bath building remains (comprising suspensurae, tiles, bricks) to explore technology and production issues. The obtained results allowed to identify local productions and to distinguish them from imports, redrawing some aspects of the historical, economic, social and technological construction context of Roman Sicily.

Abstract The investigation on the reticulation degree of volcanic alkali-activated materials, AAMs, were experimentally determined in terms of chemico-physical properties: weight loss after leaching test in water, ionic conductivity and pH of the leachate and compressive strength. Artificial neural network (ANN) was successfully applied to predict the chemical stability of volcanic alkali-activated materials. Nine input data per each chemico-physical parameter were used to train each ANN. The training series of specific volcanic precursors were tested also for the other one. Excellent correlations between experimental and calculated data of the same precursor type were found reaching values around one. The evidence of strong effect on chemical stability of the alkaline activator SiO2/Na2O molar ratio as well as the Si/Al ratio of precursor mixtures on the reticulation degree of ghiara-based formulation with respect to volcanic ash-based materials is presented. It must be noted that such effect was much less pronounced on the compressive strength values, appearing more insensitive the molar ratio of the alkaline activator. The comparison of the ANN results with more conventional multiple linear regression (MLR) testifies the higher prediction performance of the first method. MLRs results, less significant, are useful to confirm the powerful capacity of ANNs to identify the more suitable formulation using a set of experimental AAMs. This study, as few others, on the correlation between chemical stability and compressive strength of AAMs provide a great contribution in the direction of durability and in-life mechanical performance of these class of materials. Graphic abstract

This work is a part of a research project conducted in order to characterize the volcanic ash from Mount Etna, focusing in particular on the surface reactivity of ashes and possible consequence for human health. In this framework, a sampling campaign began on 16 March 2013, taking advantage of the intense volcanic activity on Etna. The interaction between volcanic ash and human organism was simulated treating two classes of representative Etnean particles with ultrapure water (grainsize of 850 um) and Gamble's solution mimic lug fluids (grainsize38 μm) with the aim to evaluate the risk due to gastric and respiratory exposure to volcanic particles. The leachates were analysed by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES), Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Ionic Chromatography (CI) in order to highlight possible dangerous elements released in water solutions according to USGS protocol. Analyses of Gamble's solution highlighted a release of elements smaller than in watery solutions and always below the thresholds established by the Italian law. On the contrary, analyses of watery solutions evidenced, for some elements (B, Cd, Ni and As), levels higher than permitted by Italian law. Considering the effects of these elements on human health, further investigations are necessary and currently carried out in order to better constrain the release process and the specific effects on human organism.

Volcanic ashes particles are subjected to substantial modification during explosive eruptions. The mineralogical and compositional changes have important consequences on the environment and human health. Nevertheless, the relationship between the speciation of iron (Fe) and the mineralogical composition and particle granulometry of the ashes, along with their interaction with water, are largely unknown. In particular, the Fe oxidation state and the possible formation of new Fe-bearing phases in presence of S, Cl, and F in the plume are key points to assess the impact of the ashes. Fragmental material ejected during volcanic activity (tephra) in 2013, was collected on the Mt. Etna (Italy) and investigated using a multi-technique approach that included conventional Electron Paramagnetic Resonance (EPR), high field EPR (HFEPR), EchoEPR, and Fe K-edge X-ray Absorption Spectroscopy (XAS). These element-selective techniques allowed obtaining a detailed information on the oxidation state and coordination environment of Fe, and of its speciation in the ash samples as a function of the granulometry. A complex mineralogical assemblage, consisting of variable amounts of nanometric crystalline Fe inclusions in a glass matrix, and of Fe-oxides and Fe-sulfur phases was revealed. A risk assessment of the ashes is attempted.

Abstract Volcanic rocks have been used for building activity by the inhabitants of important cities located on the slopes of Mt. Etna, Italy. In this paper, the potential use of volcanic residues (code 20 03 03—“Municipal waste” residues from road cleaning in the European Waste Catalogue (EWC)) for the production of alkali activated material, especially devoted to the restoration of buildings belonging to the Baroque Sicilian architecture, was investigated. In particular, large volcanic pyroclastic deposits of recent eruptions considered waste materials were studied and a volcanic paleo-soil, locally named ghiara, widely used for mortars and plaster production in XVII–XVIII century with good pozzolanic features, was also considered. Both volcanic materials were activated using different mixtures of NaOH and Na2SiO3. Furthermore, formulations with different amount of metakaolin addition (10–25 wt%) were prepared due to low reactivity of volcanic materials and to allow the activation at room temperature. X ray diffraction revealed the formation of small quantities of zeolites as a result of the alkali activation process. The mechanical-physical results evidenced that the mechanical strength is strongly dependent on the metakaolin amount (10–38 MPa); accessible porosity average 25% and an average pore diameter of 0.06 µm; water absorption range 9–15%, eluates conductivity in the range 20–350 µS/m. These results confirm the occurring of alkali activation and the good potential for these pyroclastic wastes for valorization in the restoration field. Graphic Abstract

In this paper, the potentialities of pumice-based geopolymers have been explored with the aim to evaluate their use as restoration materials. In particular, the behaviour of Aeolian pumice during alkali activation process, either alone or in binary mixtures with metakaolin, has been assessed using sodium hydroxide and sodium silicate activators. Hardened products were characterized by: X-ray diffraction; infrared spectroscopy; thermo gravimetry and electron microscopy. Furthermore, Hg-intrusion porosimetry, water absorption, compressive strength and colorimetric measurements were carried out in order to define the technical features of the produced geopolymers. The results reveal that Aeolian pumice mixed with small quantities (20–30 wt%) of metakaolin is suitable for the formation of lightweight geopolymers which exhibit an accessible porosity up to 30%, water absorption of about 18.0%, and satisfactory 28-day compressive strength up to 12 MPa. These values indicate good breathability and adaptability to the substrates of the proposed formulations. Final products display a homogeneous and compact amorphous matrix, and their colour mimic the original stones, highlighting their potential role in Cultural Heritage preservation.

Geopolymers are synthetic materials, which attract increasing interest because they represent a supplementary cementitious material as an alternative to Portland cement. Geopolymers are considered as environmentally friendly materials, due to the low processing temperature and the absence of CO2 gas emissions. These ecological features, linked to their technical properties, such as high strength, high acid resistance, and/or high-temperature resistance, make them very innovative technological materials. In addition, geopolymers show good performance if realized by the utilization of secondary raw materials (industrial wastes like fly ash or slag), thus improving strong interest in such technology from countries with growing industrialization. Here, in order to reduce global impacts and to stimulate the Sicilian green economy, we provide the evaluation of the Life Cycle Assessment (LCA) through the employ of local raw materials to produce geopolymers in Sicily. To reach this aim, geopolymers have been produced in collaboration with a Sicilian cement industry, through the use of local raw materials (furnace blast slag from Sicilian steelworks and Calabrian kaolinite) and the construction of a pilot plant. The obtained results show, for different scenarios, a considerable reduction of both CO2 emissions and energy consumption, but also a general improvement of the environmental indicators.

The evaluation of conservative treatments’ efficacy on natural building stones are usually based on standard recommendation routines finalized to evaluate compatibility and harmfulness of products in turn of the substrate. However, the visualization and the quantification of products inside pore structure of natural stones is not immediate through standard tests, so that imaging and advanced techniques are recently proposed in material conservation field to improve knowledge on penetration depth, modification of pore-air interface at different scale and monitor dynamic absorption processes. Moreover, natural stones are usually characterized by complex structure, which changes due to conservative treatments have to be inspected at different scale (from micrometer to nanometer).In this prospective, the assessment of laboratory practices able to integrate multiscale methods and give back a complete overview on interaction between new conservative formulates and natural stones is of high interest.In this paper, we propose a methodological routine for efficacy assessment of conservative products, incorporating classical and innovative nondestructive techniques. Validation of the workflow has been verified on a high porous natural stone treated with new hybrid formulates appropriately customized for conservation issues. • The study intends to add new insights on problems related to consolidation of high porous carbonate stone, application methods in consolidating natural stones and methods to evaluate efficacy of new products. • A multi-scale laboratory investigation procedure is proposed by integrating standard and innovative nondestructive methods. Merits and limits of each applied method are discussed during validation. • The possibility to incorporate standard routines and/or substitute destructive testing with non-destructive ones seem to be a valid alternative to evaluate efficiency and monitor behavior of stones treated with consolidating products. Method name: Advanced and multi-scale laboratory investigation, Keywords: Natural stones, Conservative treatments, Consolidants, Efficacy

Historical buildings of Catania city centre (Eastern Sicily, Italy) have been built for centuries using natural stone materials from local resources, including volcanic and carbonate rocks, matched in a peculiar bichromy. Particular attention is here paid on the carbonate rocks, which are generally more susceptible to decay processes. Such stones are sometimes covered by pigmented coatings with decorative purposes as well as protective function. In some cases, these nuances are partially or totally lost due to the decay processes which can also cause a modification of the chemical composition of the stone surface. The aim of this study is to prove the effectiveness of in situ X-ray Portable Fluorescence and colorimetric techniques for the characterization of degradation forms and colour modifications affecting several limestone-made historical buildings of the city centre of Catania. The results obtained, processed by means of multivariate statistical analysis, highlighted that all the stone surfaces exposed outdoor exhibit both chromatic and chemical modifications. In addition, three diverse types of superficial treatments have been identified, being related to different construction periods

The surface texture of a stone represents a sensitive parameter in evaluating its conservation state. In monuments and sculptures, in fact, external agents continuously alter the appearance of stones, determining peculiar weathering patterns and modifying properties such as retention of water and particles, interaction with light, color, and finishing. The application of protective coatings also determines changes in surface appearance of a stone, usually evaluated and monitored by color change tests. Surface metrology methods offer the possibility to quantify these changes, evaluating the impact of external agents (natural, i.e. weathering, and artificially, i.e. protective coatings) on natural stones. In this research, we demonstrate the potential of surface areal measurements in describing the evolution of weathering processes and the effects of protective treatments on porous stone materials. The obtained results suggest that the extent of the modifications is related to the scale of observation (small- vs. large-scale undulations, i.e. roughness and waviness, respectively), with an overall increase of surface roughness as the weathering proceeds. Unexpectedly, coatings based on nanoparticle dispersions increase the topographic height parameters, due to the absence of a homogeneous film.