Incorporation of Vitrified Ashes in Lightweight Foamed Concrete for 3D Printing: Thermal and Mechanical Assessment

Disposing of urban solid waste incineration residues, particularly ashes, poses significant environmental challenges. Vitrification, a process that transforms incineration ashes into stable materials, offers a promising pathway for sustainable reuse in building construction. This research focuses on incorporating vitrified incineration ashes in foamed concrete mixtures to develop building components, maintaining satisfactory thermal and mechanical properties while reducing their carbon footprint. Additive Manufacturing (AM) is a growing technology that offers remarkable flexibility to explore intricate geometries and develop highly efficient components that are often challenging to produce or unattainable with traditional techniques. A novel lightweight foamed concrete incorporating vitrified ashes was developed to produce 3D-printed wall components, and its thermal and mechanical properties were assessed. The printability of the material was evaluated utilizing Liquid Deposition Modelling (LDM) with a DeltaWASP 40100 3D printer. The thermal conductivity of cast samples, and the flexural and compressive strength of 3D printed specimens were assessed experimentally. The results were compared with baseline samples (without vitrified ashes). ASTM C518 standard was used to make the thermal assessment, and UNI EN 196-1 regulation was followed to perform the mechanical tests. Results show that the incorporation of glass ashes determines a negligible alteration of the thermal properties. By comparing 3D-printed specimens, flexural strength decreases while compressive strength significantly improves (up to 31% more compared to the baseline samples). Overall, this approach underscores the potential of 3D printing incorporating waste materials in the admixture to develop efficient, high-performance wall components for the building sector.