Chinese design studio BENTU Design has developed a method for turning construction rubble from demolished urban villages into 3D printed public furniture, with the resulting material containing up to 85% recycled solid waste. The project, called Inorganic Growth, has produced two pieces so far: a chair called PU and a stool called YOU, both fabricated from crushed concrete, brick rubble, and mortar.
The material preparation process is technically demanding. Demolition debris gets processed through a jaw crusher for primary crushing, then through an impact crusher for secondary shaping. Multi-layer vibrating screening separates aggregates by particle size. The fine powder fraction, which makes up roughly 30 to 35% of the waste stream, undergoes mechanical and chemical activation before being combined with industrial by-products including fly ash, slag powder, and silica fume to create a cementitious binder. Coarse aggregates in the 3 to 6 mm range form the structural backbone of the printable mix.
To address the high water absorption that typically plagues recycled aggregates, BENTU applied nano-suspension surface modification, cutting water absorption from 8–10% down to 3–5% and boosting the strength of the interfacial transition zone by over 40%. Thixotropic agents and AI-assisted mix optimization keep the material printable while maintaining structural performance. The finished furniture achieves a compressive strength of 106.25 MPa and a flexural strength of 12.28 MPa.
The color palette isn’t applied after the fact. It’s derived directly from the demolition sites themselves. BENTU used image-processing algorithms to analyze photographs of demolished villages and extract representative color values from the rubble: iron-red tones from brick, cement-gray from concrete, muted greens from weathered surfaces, and blue-green hues from glazed ceramic fragments. Using dual print heads and Fused Deposition Modeling, the studio built a gradient control system that distributes pigment along the vertical print axis, creating chromatic transitions that mimic stratified geological cross-sections.
Perhaps the most operationally interesting aspect of the project is the mobile processing unit. By installing crushing, sorting, and printing equipment directly at demolition sites, BENTU says it’s achieved a material utilization rate of 92%. Intelligent slicing algorithms cut material consumption by an average of 40% without compromising structural performance.
The PU chair measures 715 x 580 x 720 mm and weighs 110 kg. The YOU stool measures 580 x 430 x 540 mm and weighs 70 kg. Both are available in five colorways: Ink Wash, Ink Green, Vermilion, Tea Brown, and Celeste, and both share identical structural specifications. Untreated water absorption sits at 1.73%, dropping to 0.34% after waterproofing treatment.
Source: designboom.com
