Fabrizio Antonelli

The conservation of the UNESCO World Heritage site of the Sassi di Matera requires an evaluation of consolidation strategies for Gravina calcarenite, a highly porous calcareous stone extensively used in the historic built environment. The pore system, characterized by a predominance of macropores combined with a significant microporous fraction, plays a key role in the performance and long-term behaviour of consolidating agents. Although consolidation treatments have been widely investigated for carbonate stones, studies specifically addressing Gravina calcarenite remain relatively limited. This study presents a comparative assessment of the performance and durability of four commercially available strengthening agents: an ethyl silicate-based product, two nanolime formulations, and a nanosilica-based treatment. The products were applied to Gravina calcarenite and evaluated using a multi-analytical approach integrating mercury intrusion porosimetry, water absorption assessed by the contact sponge method, ultrasonic pulse velocity (UPV), colorimetric measurements, and artificial aging tests. The results reveal distinct performance trends: the ethyl silicate-based product shows the most pronounced immediate reduction in water absorption, together with a consistent increase in UPV, although these effects are not retained after aging. The more concentrated suspension of Ca(OH)₂ nanoparticles (50–250 nm) exhibits a moderate reduction in water absorption with limited chromatic impact, although a decrease in effectiveness emerges after aging. In contrast, the Ca(OH)₂ nanoparticle suspension (100–300 nm), dispersed in isopropanol at a concentration of 5 g/L, shows more limited and variable changes across the investigated parameters. The nanosilica-based treatment shows a reduction in water absorption and the largest mean increase in UPV after application, although with greater variability among specimens, together with modifications in the finer and intermediate pore fractions. None of the investigated products provided a uniform and persistent improvement across all evaluated parameters. Overall, the evaluation of the investigated properties provides a basis for assessing treatment performance and supporting informed conservation strategies.

The preservation of Europe’s stone-built heritage is crucial for safeguarding our cultural legacy. This study investigates twelve distinct stones used in historical monuments across Italy, Spain, Greece, and Norway, including marbles (Carrara and Macael), limestones (Botticino, Red Verona, Costozza, Istrian, Sfouggaria, Santa Pudia), a carbonate-dominated sandstone (Lartios), volcanic rocks (Euganean trachyte and Tønsberg latite), and an intrusive igneous rock (Tønsbergite). Through comprehensive analysis of mineralogical composition, porosity, water interactions, and accelerated ageing tests, this research establishes a framework for assessing these materials susceptibility to decay mechanisms. The results demonstrate significant variability in durability and decay response among the stone types, primarily determined by pore abundance and distribution. This study enhances the understanding of stone materials behaviour under stressed conditions, offering valuable insights for mitigating future decay processes and protecting European cultural heritage. The stones examined were chosen for their significant presence at the four pilot sites of the European Hyperion project: Venice (Italy), Granada (Spain), Rhodes (Greece), and Tønsberg (Norway). Graphic abstract

Cultural heritage assets face significant threats from climate change and land subsidence, leading to extensive social, economic, and environmental losses, and damage to artistic and monumental heritage in Italian coastal cities. In particular, addressing these challenges in the Venetian context necessitates the development of an adaptation plan for the lagoon area and the identification of targeted intervention strategies to preserve cultural and territorial heritage. To address these objectives, a systematic study was conducted to investigate the deterioration patterns exhibited by the most representative lithologies used in Venetian buildings. Thirty samples of five carbonate stone varieties subjected to natural aging were monitored in six different areas of Venice’s historic center and on Torcello Island, selected based on altimetry relative to tidal zero and exposure to environmental forces. An integrated multi-analytical approach was employed to identify and map macro- and micro-morphologies of stone surfaces related to chemical weathering and physical decay. Stones underwent evaluation during nine monitoring periods using various tests (ultrasound P-wave velocity and colorimetric measures) and analyses (µX-Ray Fluorescence, X-ray powder diffraction, stereomicroscope observations, and recognition of biological patinas). Data processing aimed to elucidate how microclimate and intrinsic stone features influence the occurrence and progression of deterioration phenomena. From the experimental findings, a Stone Deterioration Index and Intervention Procedures (SDIi) were proposed to estimate deterioration rates and assess the need for targeted intervention through conservative actions.

The HYPERION EU project aims to develop a Decision Support System to improve resilience and sustainable reconstruction of historic areas faced with climate change and extreme events. In this context, Venice presents an outstanding example of urban and architectural complexity and richness. The mapping of the ornamental stones of the façade of the Venice Clock Tower (Torre dell’Orologio) and their deterioration patterns acts as a milestone on which to build the knowledge-acquisition process of the system as regards stone artefacts and their decay products. The Clock Tower is an early Renaissance building (1499) in Lombardesque style and stands over the entrance to the Mercerie on the northern side of St. Mark’s Square. Detailed surveys and mapping of both building materials (mainly stones) and deterioration patterns were carried out, the latter following the glossary of weathering forms, coupled with an easy-to-use scale of evaluation of their intensity. The data output consists of several monothematic maps which can be handled separately, each one focusing on precise lithological or specific deterioration aspects. This study also proposes a simple approach to summarizing the total state of deterioration of the building in the form of a Total Deterioration Rank (TDR) and its representation. The stones used in the façade are regional (Ammonitico Rosso and Scaglia Rossa) and extra-regional limestones (Istrian Stone), as well as Mediterranean white and coloured marbles and stones already used in antiquity (i.e., Fior di Pesco or marmor chalcidicum, lapis porphyrites, a volcanic rock from the Egyptian Eastern Desert, Proconnesian marble from the Island of Marmara, Pavonazzetto toscano and white Carrara marble from the Italian Apuan Alps). The most frequent forms of deterioration detected are black crusts, patinas, discoloration and patterns linked to erosion processes. The interrelation of different mappings led to a number of useful considerations concerning differences in the effectiveness of maintenance procedures between public and private management of the monument.

This paper examines eight marble samples from the architectural elements and liturgical furniture of the ecclesiastical complex of Santa Giustina in Padova (Italy), founded by the Rufus Venantius Opilio before AD 524. The provenance determination of the marbles was carried out by means of a multi-analytical approach combining mineralogical–petrographic investigations, performed by microscopic observations of thin sections, and the measurement of the ratios of stable carbon and oxygen isotopes. The results obtained were compared with up-to-date petrographic and isotopic databases (Antonelli and Lazzarini 2015), and they showed that the analyzed marbles come from the quarries of the island of Proconnesus in Asia Minor, modern Marmara Adası (Turkey). Archaeometric evidence, together with the stylistic and functional analysis of the pieces, suggests the direct importation of a complete set of sculptures, shipped at different stages of workmanship from the workshops of Constantinople and expressly ordered by a single patron, who can be identified as Opilio, founder of the basilica of Santa Giustina and praetorian prefect at the court of King Theodoric.

This paper presents the results of the characterisation, identification, provenance determination, and quantification of the white, greco scritto-like and polychrome marbles used for architectural purposes at Forum Sempronii, a Roman town in the Marche region of Italy. Samples of five fragments of white marble and one fragment of a greco scritto-like marble have been studied using mineralogical and petrographic observations and stable isotope ratio analysis (SIRA) of carbon and oxygen. Polychrome marbles were macroscopically identified by comparison with reference samples and available image databases. Analytical results of the white and greco scritto-like marbles identified the material as coming from the quarries of Carrara (Luni, Italy) and Proconnesos (Marmara, Saraylar, Turkey) for white marble, and of Ephesos-Hasançavuslar for greco scritto-like marble. Further, at least eleven imported polychrome stone varieties were distinguished. The study clearly illustrates that Forum Sempronii had access to the main marble trade networks of the Roman Mediterranean. The early attestation of Proconnesian marble at the town’s augusteum (i.e., Augustan date) is unique for central Adriatic Italy.