San Nicola in Carcere, one of the minor basilicas in the historical center of Rome, was the location of a wide investigation campaign of the water-related deterioration causes, present in the lower sector of the apse and adjacent pillars, affected by water infiltrations, mould and salt efflorescence. The results obtained identify the presence of water content and related effects mainly on the sides of the apsidal wall. This work focuses on the use of five Non-Destructive Techniques (NDT) and intends to show the gains obtained by integrating widely interdisciplinary methods, namely the Infrared Thermography (IRT), the Unilateral Nuclear Magnetic Resonance (Unilateral NMR), the Acoustic Tomography (AT), the Acoustic Imaging (AI) and the Laser-Induced Fluorescence (LIF). All the techniques contribute to the rapid, non-invasive and early identification of the moisture distribution, while some of them (LIF and AI) also address the determination of some moisture effects. The integrated use of different techniques helps to take the multidisciplinary point of view necessary to formulate an effective restoration intervention based on a sound scientific rationale; nonetheless, it allows to experiment a holistic approach, verifying the potential of a wide range of NDTs available within the context of a restoration yard.

The earthen architecture widely spread in many countries of Europe, America, Asia, Africa, testifies to a particular material and immaterial culture. Nevertheless, it is a fragile heritage, which needs continuous maintenance. To encourage the preservation of such evidence of building techniques, an experimental campaign aimed at the development and evaluation of the performances of protective earthen plasters was undertaken. The durability of the plasters was improved through the addition of different additives, some of them traditional (such as lime and gypsum) and others innovative (geopolymers, enzymes), and resulting from industrial wastes (cement kiln dust). These additives have been selected considering low production costs and a reduced environmental impact, to improve the sustainability of the interventions. The performances of the earthen plasters in terms of efficacy (resistance to water erosion, water absorption, drilling, thermo-hygrometric cycles) and compatibility (changes in color and water vapor permeability) have been evaluated. Good performances were obtained by the different mixtures and, in particular, by those stabilized with gypsum. The results of this experimentation could find a useful application in the preservation of both ancient and new earthen built heritage.

Handheld X-ray Fluorescence devices (HH-XRF) have given archaeologists and conservators the opportunity to study a wide range of materials encountered in their work with great accessibility and flexibility. The investigation of copper-based artefacts is a frequent application of these instruments in the field of cultural heritage as it gives direct and rapid quantitative results that can provide very important information about them, such as their fabrication technology. This paper discusses the comparison of quantitative results, obtained by a commercial handheld XRF device “Bruker Tracer 5g” on certified standards, compositionally significant in copper-based alloys of interest in the field of cultural heritage. The measured elemental concentrations were derived using three different calibrations, which were examined for their accuracy. Two of them were based on the empirical coefficients approach, performed by the built-in calibration/software (copper alloy calibrations provided by Bruker manufacturer and the Bruker EasyCal software), while the third one was performed off-line by processing the spectra with an independent fundamental parameters (FP) software (PyMca version 5.9.2., a X-ray fluorescence analysis software developed at the European Synchrotron Radiation Facility). The results highlight that although HH-XRF devices simplify data collection, for optimal quantitative results, the correct choice of analysis conditions and calibration method still requires a detailed understanding of the principles of X-ray spectrometry.

Conservation of hypogea and their accessibility by the visitors is a hard question, due to the interaction of different factors such as the intrinsic characteristics of the hypogeal environments and the presence of public. A particular case is represented by the Mithraeum of Marino Laziale, located a few kilometers away from Rome and accidentally discovered in the 1960s. The uniqueness of the discovery was the presence of a well-preserved painting of the Mithraic scene (II century A.D.) probably due to the oblivion of the place of worship over the centuries as well as the isolation from the outdoor environment. Unfortunately, despite a recent complete restoration and recovery of the archaeological area, which ended in 2015, the area was never open to the visitors and only two years after completing the works it was no longer safe to use. Hence, the need for a new planning of interventions starting from the deep knowledge of this cultural heritage and from the analysis of past incorrect actions to arrive at the opening—without any risk for the archaeological findings and visitors—and management of this site, never exposed to the public. Therefore, since 2018 a diagnostic campaign and microclimate monitoring have been started. The data collected during the two years of investigations have been fundamental to assess the conservation state of the hypogeal environment and the potential risks for the preservation of the three paintings (the Mithraic scene and two dadophores). Long-term monitoring of indoor environmental conditions assumes the role of an essential tool for the planning of preventive conservation strategies but also for the control of the site after its opening to the visitors. Furthermore, the characterization of the microclimate is non-invasive, sufficiently economical and accurate. In this paper, the characterization of surfaces in the Mithraic gallery through optical microscopy, UV fluorescence/imaging techniques, FT-IR spectroscopy, XRD and the microclimatic parameters variation in the presence or absence of visitors are used to define the strategies for the opening and fruition of the Mithraeum. The strategies for the sustainable fruition of this unique archaeological site have been defined through a conservation protocol approved by the Italian Ministry of Cultural Heritage and necessary for the site managers and curators of the Municipality of Marino Laziale to finally support its opening.

Earthen architecture, by its nature, is a fragile because it has a poor resistance toward the action of weathering, which has also increased in recent years through the effects of climate change. The presence of interesting examples of earthen brick buildings, for example, in the Piedmont Region of Italy, is characterised by the absence of rendering, which reveals the need to test treatments for the protection and/or strengthening of the walls of these buildings. This action is of fundamental importance to improve its resistance to the aggressive action of atmospheric agents and avoid their disappearance. A testing campaign adopting protective products with sustainability characteristics and low environmental impact was carried out on earthen brick walls. Different products belonging to various categories (synthetic polymers, natural resins, nano-structured materials) and selected based on previous experiments or tested for the first time on earthen surfaces were selected. The performance assessment of the products was carried out by taking into account the standardised procedures in the field of cultural heritage conservation through the following tests: water absorption, water vapour permeability, drilling resistance, water erosion tests (Geelong and spray), contact angle measurements, colorimetric measurements, and ageing tests. Although the choice of the optimal protective product should be made on a case-by-case basis, where it is not sustainable to proceed in this way, the results of this experimental campaign—in the presence of materials and weathering conditions similar to those of the case study analysed—will provide indications in identifying of the most appropriate product.