During the first 18 months, ATRIUM achieved substantial technical and scientific progress, advancing from material design to pilot‑scale validation of bio‑based construction solutions. Activities covered the full technological chain, including material formulation, process optimisation and functional characterisation in view of integration into final products.
Significant progress was made in developing and upscaling bio‑based materials. Bio‑PE composites with recycled organic fillers were optimised for co‑extrusion and foaming, identifying formulations with high bio‑based content (>95%), suitable melt strength and controlled foaming behaviour. These materials were produced at pilot scale in batches of several hundred kilograms, meeting density and processability targets for lightweight decking.
In parallel, PHA‑based biocomposites reinforced with hemp and softwood fibres were developed for injection‑moulded applications, notably planting pots for modular green walls. Mechanical, thermal and rheological tests showed performance comparable to fossil‑based benchmarks, with two formulations scaled up to 60 kg and validated through industrial injection moulding.
Cellulose‑acetate composites reinforced with hemp fibres were also developed for additive manufacturing to produce a green wall. A formulation with 5 wt.% hemp fibres was selected after systematic screening and compounded at 50 kg scale for large‑format 3D printing.
Major advances were achieved in mycelium‑based materials through multilayer acoustic and insulation panels, improving fire performance, dimensional stability and acoustic absorption. Fire testing confirmed a B‑s1‑d0 classification, panel dimensions were increased to 120 × 160 cm, and production exceeded 1,000 m².
To address bonding and moisture sensitivity, a fructose‑based bio‑adhesive was developed, significantly improving internal bond strength, while further optimisation is ongoing. Hemp‑lime mixtures were also formulated for extrusion‑based additive manufacturing, achieving stable extrusion, good buildability and dry densities around 1,000 kg/m³, suitable for non‑load‑bearing blocks.
Overall, ATRIUM validated four innovative processing routes—co‑extrusion with foaming, mycelium bio‑manufacturing, extrusion‑compounding with injection moulding, and additive manufacturing—at pilot scale, providing a strong basis for upcoming demonstration and performance assessment phases.
