Davide Nonis
The ornamental stone industry generates significant volumes of waste during the extraction and processing stages—mine tailings and sawdust classified as aggregates (EWC 01 04 13)—which, despite their classification, pose environmental risks if managed improperly and which current reuse pathways (as filler for bituminous mixtures, as a additive for bricks) only partially address. In this context, this PhD research investigates whether the alkaline activation of stone waste can support both a portfolio of new solutions and a recycling system rooted in the territory of origin. The work lies at the intersection of technical architecture and systems design, with two application strands—3D printing and conglomerates for road paving—developed in parallel. The project area is the province of Verbano-Cusio-Ossola (Piedmont, Italy), with Assograniti VCO and the funding partner Moro Serizzo acting as the main points of contact. The methodology alternates between divergent and convergent phases, comprising a two-stage literature review, the laboratory development of geopolymer formulations, and a holistic assessment of the local area. Preliminary results include the identification of parametric design as the optimal modelling approach for 3D printing, the definition of a five-stage validation chain for the printed mixtures, and the formulation of a more fluid mixture specifically adapted for the production of conglomerate, which has produced visibly more homogeneous samples now ready for mechanical characterisation. Further field research, together with the planned characterisation campaigns, will provide the empirical basis for assessing whether the system can effectively support local upcycling and, once established, be transferred to other areas facing similar challenges with stone waste.
Keywords: Geopolymers, alkali-activated materials, ornamental stone waste, sawing sludge, 3D printing, pavement conglomerates, systemic design, circular economy, territorial valorisation, Verbano Cusio Ossola