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International audience; This research is part of the PON (Programma Operativo Nazionale) SINAPSIS (SIstema NAzionale Protezione SIti Sensibili), an interdisciplinary project combining archaeological and archaeometric methods. This paper focuses on frescoes from one of the 70 funeral monuments belonging to "Porta Mediana" Necropolis, a very interesting archaeological context located in Cuma, dating back to the first half of the 3rd century BCE. The study provided detailed information on pigments and colors acquired both on untreated and treated (restored) frescoes. Portable colorimetry and chemical-mineralogical (Raman spectroscopy and X-ray powder diffraction-XRPD, respectively) analyses were performed in situ and on collected samples in order to: 1) identify pigments, raw materials and provenance, 2) point out possible color changes caused by conservative treatments and/or weathering. The identified palette is typical of the Roman period; it includes both single and mixtures of two or more pigments to obtain particular hues. Moreover, the identified raw materials, such as red and yellow ochres, green frit and Egyptian blue, clearly highlighted the choice to use raw materials from local sources. The use of expensive coloring materials also suggests that the mausoleum belonged to a family or a group of people with a high social status.

This research aims to deepen knowledge on geomaterials used in building operations of a very important monumental complex belonging to the "Porta Mediana" necropolis the archeological site of Cuma. The entire site counts 70 mausoleums among which, the one named "Sphinx complex" or A63, is particularly important. For its realization several geomaterials have been used. Analytical results were carried out from several techniques such as optical microscopy, microchemical and mineralogical-petrographical analysis, scanning electron microscopy with EDS and X-ray powder diffraction. This approach allows to clarify the provenance of natural geomaterials and also the technological processes involved in the production of artificial geomaterials (mortars, plasters, cocciopesto). Phlegrean tuffs, due to their easy workability and good mechanical features, were used mainly for masonries and for decorative function (a bas-relief of a "sphinx" for example). As far as artificial geomaterials are concerned, the use of a volcanic aggregate, was privileged too. Some examples of imported stones were also found: limestones and marbles, the first one implemented as a building material for cippi of the fence while the second one for prestigious coating elements. Results permitted to evaluate building techniques of the period and mainly the wide potential of Phlegrean fields' materials when used as a bulding stone. This research aims also to give important informations for restoring and conservative actions useful for mausoleums of the entire site.

Roman mortars from a mausoleum (named D46b) belonging to the archaeological site of Porta Mediana necropolis, in Cuma (Naples, Southern Italy) have been studied by means of petrographic, mineralogical and micro-chemical analyses. The aim of this research is to fill the knowledge gap regarding mortar-based materials used in Roman age within this wide archaeological site. Two typologies of mortars (bedding and coating) were collected from mausoleum’s masonry. They were lime-based with addition of pozzolanic materials, according to Vitruvius’ recipe. Raw materials, such as volcanic sand and limestones, mainly from local sources, were preferentially used as aggregate, both for great availability and good properties. As regard production techniques, the multi-layer feature of the coating mortars, once again shows the great knowledge of the building art. Each layer is the result of a precise choice, as shown by the differences both in texture and petrographic features. Data from detailed mortars characterization have infer the outstanding skill of Roman craftsmen, as already proved by extraordinary durability of buildings. The research was very useful not only to increase the knowledge of this ancient culture but also to planning conservative actions, that, through mortar reproduction or the research of suitable materials, can promote the safeguard of this invaluable heritage.

This paper reports a detailed study on some relevant portions of the main façades of Caserta Royal Palace (Reggia di Caserta), one of the most important Italian monuments, comparable for its impressive architecture to the Royal Palace of Versailles in France and considered the largest royal palace in the world by volume. The research was focused on the weathering pathologies affecting the stone surfaces that, in the last decades, suffered several detachments of fragments from the coatings and from other architectural elements such as string courses, eaves, and capitals. A preliminary characterization of the materials of the façades and an evaluation of the relative weathering pathologies provided the information required for appropriate restoration and securing of these portions of the building. In particular, an innovative evaluation procedure which draws on techniques typical of the earth sciences allowed the proposal of a ‘risk attitude’ applied to discrete portions of the geomaterials used in the built heritage which is based on the influence of different factors leading to weakening of the stone and to the final detachment of rock fragments. Such a large and complete set of information should be carefully considered by the project planners to adopt the required steps for a suitable risk mitigation and for securing the site during restoration.

This paper focuses on the authigenic mineralization processes acting on “Tufo Rosso a Scorie Nere” (TRS), i.e. one of the main pyroclastic units of the Vico stratovolcano (Latium, Italy). The pyroclastic deposits appear in general massive and made of “black vitreous vesiculated juvenile scoriae”, immersed in an ashy matrix lithified after zeolitization processes. The main minerals are chabazite and phillipsite, and the zeolitic content is locally variable, reaching 68 % wt. Zeolites grow replacing both amorphous fraction and pre-existing phases, occurring inside both matrix and scoriae. Concerning scoriae, zeolitization moves from the rim to the core of the scoriaceous fragment as a function of (a) temperature of the fluids and (b) permeability (primary or secondary). Composition of parental fresh glass and that of zeolitized rocks is compatible with trachyte chemistry, lightly undersaturated in SiO2, and the alteration processes modified the parental rock chemical features. Zeolites genesis is ascribed to a “geoautoclave-like system”, and zeolites display a Si/Al ratio similar to that of the parental glasses. TRS presents promising mineralogical characteristics as supplementary cementitious material in the production of mixed cements.

Ancient pozzolanic mortars show the high technological quality achieved by Roman construction workers, due to their ‘excellent state’ of preservation in every environment. These workers well knew that thanks to the combination of lime with specific volcanic products (pozzolana), mortar and concrete become hydraulic, allowing underwater hardening and increasing mechanical strength. The use of pozzolana in a mortar provides the underwater curing (hydraulic limes) of whatever construction with higher speed compared to carbonation processes of slaked lime. Whenever pozzolana is not available, it is substituted by ceramic fragments, which possess similar hydraulic properties. This research focuses, for the first time, on the detailed characterization of mortars coming from the Thermal Complex of Baia, which represents one of the most important archaeological sites in the Campania region. Thanks to several thermal springs, the ancient city of Baiae (Campi Flegrei) was the holiday resort of the Roman aristocracy. The former Soprintendenza Archeologia della Campania, allowed us to perform non-invasive, but representative, sampling of mortars that were characterised by multianalytical methodologies (POM, XRPD, SEM-EDS, TGA, and MIP) providing useful information on possible future activities of restoration. Results confirmed the expertise of Roman workers, who skilfully combined volcanic tuff aggregate, hydrated lime, and ceramic fragments. In particular, the typical zeolitic mineral association of phillipsite > chabazite > analcime found in the tuff aggregate pointed out their provenance from the Neapolitan Yellow Tuff related to the volcanic activity of Campi Flegrei of ca. 15 ka BP. The most relevant characteristic detected in all studied samples is the mortar hydraulicity testified by evidences such as reaction rims between pozzolana and binder, Hydraulicity Index (HI), and thermal analyses investigation. Also, composition of secondary mineralogical phases in the cementiceous matrix is particularly relevant. Distinctive is the contemporary presence of C-A-S-H gel, calcite and gypsum. C-A-S-H gel is derived from lime/ceramic fragments reaction; calcite is likely related to the partial reaction of underburned lime; and gypsum could be ascribable to the sulphation process of calcite. These secondary minerogenetic products fill pore space and enhance bonding in pumice fragments, thus contributing to long-term durability of mortars.

The Sabatini Volcanic District belongs to the Roman magmatic province of Central Italy, and the Tufo Giallo della Via Tiberina was one of the most voluminous pyroclastic flow-forming eruptions in this district. Post-depositional processes strongly affected this pyroclastic flow deposit leading to the crystallization of different authigenic phases (chabazite, phillipsite, feldspar). A field volcanological survey, along with a careful mineralogical characterization of a large amount of samples of the lithified facies, allowed us to reconstruct a type section primarily based on the amounts of the main authigenic phases. Chabazite always prevailed over phillipsite throughout the entire section, although in the innermost portions of the deposit, where temperatures remained high, chabazite mostly converted into a more stable phase such as an adularia-like phase. In addition to the zeolitization process, the fairly strong mechanical properties of this tuff can be also ascribed to the diffuse occurrence of microcrystalline calcite, which re-precipitated as a secondary phase after the dissolution of carbonaceous clasts.