Innovative waste-containing 3D-printed geopolymer structures for enhanced acoustic comfort in built environments

The reduction of noise pollution in buildings, a critical global public health concern, demands the development of novel acoustic barriers that meet with the sustainability requirements envisioned for future building materials. Herein, additive manufacturing was explored to develop 3D-printed geopolymer structures combining high porosity, mechanical strength, and remarkable acoustic properties, a pioneering study in this area. The results demonstrate that lattice design can effectively tailor the acoustic performance of these novel materials. A 21-mm thick structure with filaments rotated by 45° between layers exhibited an impressive sound absorption coefficient across the studied frequency range (α reaching 0.90 at 3150 Hz) alongside a compressive strength (6.9 MPa). In contrast, a structure with filaments rotated by 90° showed slightly lower sound absorption performance (α = 0.84) but significantly higher strength (12.6 MPa). These promising findings could pave the way for the broader use of environmentally conscious geopolymers in acoustic applications.