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

No abstract

Alkali-activated materials (AAMs) and "geopolymers" are inorganic polymeric materials obtained by mixing of solid aluminosilicate precursors with an alkaline solution (generally, KOH or NaOH and Na 2 SiO 3 mixed in various ratios). This class of aluminosilicate materials has emerged as a greener alternative to traditional concrete, for large-scale as well as for niche applications such as conservation and restoration of built heritage. In this work we apply Raman

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.

No abstract