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 Na₂SiO₃ 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 spectroscopy both to aluminosilicate precursors (metakaolin, pumice, volcanic ash, volcanic soils, clayey sediments, ceramic waste) and to the respective AAMs. In the field of vibrational spectroscopy, Raman is much less employed in the literature with respect to Fourier transform infrared (FTIR) to have insights into the alkali activation process from a molecular point of view. The aim of this paper is to investigate the potentiality of a Raman approach to the comparison of the employed raw materials with the respective AAMs. Raman analyses during the first hours of geopolymerization were also carried out on the clayey sediments and ceramic waste‐based products. The results, differentiated according to the employed precursors, exhibit spectra relative to crystalline and amorphous phases that can give an indication about the newly formed aluminosilicate gel.

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.

This paper aimed to investigate the possibility of using alkaline-based binders made from the industrial waste produced by ceramic tiles in the field of conservation and the restoration of monuments and archaeological heritage. Geopolymer mortars, which are environmentally sustainable products obtained by chemical consolidation at room temperature, are studied for their versatility in applications as reintegration or bedding mortars and pre-cast elements, namely bricks, tiles or missing parts for archaeological pottery, as an alternative to traditional not sustainable products. Starting from a well-established formulation, the function of the product, meaning its technical characteristics and its workability, was optimized by changing the aggregates used, by adding a Ca-rich compound or by changing the liquid/solid ratio with the use of tap water. The possibility of tailoring the finishing of the obtained products was also evaluated. X-ray diffraction analysis showed the influence of adding the additive with the presence of newly formed phases, which positively affect the product’s workability. On the contrary, no important variations were observed with the increase in the water content of the same formulation, opening up the possibility of managing it according to the required fluidity of the final product. Good results were observed, jumping above the laboratory scale and overcoming criticalities linked to the variabilities on site and the higher volume of materials used for industrial processes. The present research also demonstrates that ceramic-based geopolymers are suitable for application in a large variety of cultural heritage projects and with different purposes. Therefore, the paper encourages the use of alkali-activated mortars for green restoration, specifically given the wide range of ceramic materials.

The recent upgrading of synchrotron radiation (SR) sources has favored, in the last few years, the construction and design of beamlines optimized for the study of cultural heritage materials, which may require ad hoc setups, specific spatial resolutions, and detection limits. In the field of cultural heritage, integrated approaches combining different techniques are often required, even at large facilities, where some beamlines offer the possibility of performing different types of measurements at the same point of analysis, complementing preliminary information usually obtained by conventional laboratory and/or portable in situ methods. An overview of the last ten years of synchrotron applications for the study of pigments is given, with discussion of upstream and downstream challenges to methods and techniques. The possibilities offered by the synchrotron techniques are illustrated by a case study of a particular class of painted ceramics, as an example of different research questions that are solved by a combination of SR-based methods.