Engineers hope to print Lego-style bricks from building waste

Backed by funding from the EU Commission, the team behind the three-year DigiMat project hopes to develop and demonstrate an eco-friendly cement mix, created from building waste, that can be ‘printed’ into Lego-style blocks for use in new buildings.

“Demonstration projects built over the past few years have shown both the viability and potentials of 3D printing technologies,” said project lead Dr Seyed Ghaffar, an associate professor in civil engineering at Brunel. “However, these projects have used conventional raw materials in their concrete feedstock. The use of recycled waste driven secondary raw materials to replace virgin aggregates for 3D printing of a building block has not yet been done, but we hope to demonstrate it with this project.”

DigiMat hopes to reduce the construction industry’s reliance on cement but offering a clean and affordable solution that reuses materials recycled from other buildings.

The team ultimately plans to demonstrate the technology by using additive manufacturing to print out a series of 500mm x 500mm recycled bricks that slot together to form an interlocked wall.

“Nearly half of all materials extracted from Earth annually are used in concrete, and extraction of construction virgin aggregates is the main part of the global non-metallic mineral consumption,” said Dr Ghaffar, who heads the Additive Manufacturing Technology in Construction (AMTC) research group. “Our objective is to decrease the CO₂ footprint of printed products against traditional virgin concrete and cementitious mortars, through the development of printable mixtures that will use up to 100% recycled aggregates."

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