Display omitted •Reuse of Sicilian volcanic residues as precursors for alkali-activated materials.•TGA, TG coupled to FT-IR and X-ray µCT have been used to define the influence of reactants.•Multidisciplinary approach for the optimization of the mix design. Insights on thermal behavior and microstructures of AAMs based on Sicilian volcanic precursors (i.e., volcanic ash, “ghiara” and pumice) have been performed. A multidisciplinary approach by means of thermogravimetric analysis coupled to Fourier Transform Infrared Spectroscopy and X-ray Computed Microtomography has been used with the aim to define the influence of reactants involved in the process. The obtained results show: i) the increase of metakaolin shifts the gas emission toward lower temperatures; ii) the positive relation between mass loss and liquid/solid ratio; iii) the influence of particle size of precursors on the pore development.