Low carbon concrete for modern methods of construction

The project focuses on developing printed Lego-style bricks from waste construction materials. Backed by funding from the EU Commission, the investigators behind the three-year project hope to develop and demonstrate an eco-friendly cement mix, created from building waste, that can be easily printed into new, tight interlocking 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, 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. Construction, driven by its use of cement, is currently one of the world’s worst polluting industries, producing up to 0.85 tonnes of CO2 for every tonne of cement.

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 this technology by printing out a series of 50cm x 50cm recycled bricks which will be slotted together to form an interlocked wall in a similar fashion to one built from Lego.

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.”

Publications

1- Karla Cuevas, Mehdi Chougan, Falk Martin, Seyed Hamidreza Ghaffar, et. al. (2021). 3D printable lightweight cementitious composites with incorporated waste glass aggregates and expanded microspheres–Rheological, thermal and mechanical properties. Journal of Building Engineering

2- Mehdi Chougan, Seyed Hamidreza Ghaffar, et. al., (2021). Investigation of additive incorporation on rheological, microstructural and mechanical properties of 3D printable alkali-activated materials, Materials and design

3- Pawel Sikora, Mehdi Chougan, Karla Cuevas, Marco Liebscher, Viktor Mechtcherine, Seyed Hamidreza Ghaffar, et, al.,. (2021). The effects of nano- and micro-sized additives on 3D printable cementitious and alkali-activated composites: a review. Applied Nanoscience

4- Mehdi Chougan, Seyed Hamidreza Ghaffar, Mohammad Jahanzat, Abdulrahman Albar, Nahzatullah Mujaddedi, Rafiq Swash. (2020). The influence of nano-additives in strengthening mechanical performance of 3D printed multi-binder geopolymer composites. Construction and Building Materials

5- Abdulrahman Albar, Mehdi Chougan, Mazen J. Al- Kheetan, Mohammad Rafiq Swash, Seyed Hamidreza Ghaffar. (2020). Effective extrusion-based 3D printing system design for cementitious-based materials. Results in Engineering