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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.”

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Columns being printed to assess the buildability of low-carbon concrete
Columns being printed to assess the buildability of low-carbon concrete
Columns being printed to assess the buildability of low-carbon concrete
Columns being printed to assess the buildability of low-carbon concrete
low carbon concrete printing
low carbon concrete printing


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

Low carbon concrete

Meet the Principal Investigator(s) for the project

Dr Seyed Ghaffar - Dr Seyed Ghaffar is an Associate Professor in Civil Engineering. He is a Chartered Civil Engineer (CEng, MICE), a Member of the Institute of Concrete Technology (MICT) and a Fellow of the Higher Education Academy (FHEA). He is the leader of Additive Manufacturing Technology in Construction Research Group (AMTC). The focus of AMTC is on valorising construction and demolition waste using materials science and 3D printing to achieve the circular economy goals of sustainable construction. Dr Ghaffar, as the Principal Investigator, has been successful in securing a €220K project funded by the H2020 EU Commission on ''Digital fabrication and integration of Material reuse for environmentally friendly cementitious composite building blocks (DigiMat)' 2021-2023. Dr Ghaffar is the Principal Investigator of a £300K project funded by the British Council (Institutional Links) on 'Direct Writing of Cementitious Inks to Scaffolds with Complex Microarchitectures (DiWoCIS)' 2020-2022. He is also the Principal Investigator of a £300K project funding from the Engineering and Physical Sciences Research Council (EPSRC) on 'High-Performance Compressed Straw Board (HP-CSB): A New Generation of Building Materials' 2018-2022. Dr Ghaffar's research covers a number of construction materials, with a focus on the development of low-carbon technologies suitable for new and retrofitting applications by combining materials sciences and innovative technologies. Dr Ghaffar is the Executive Editor of the Journal of Results in Engineering (Elsevier)   He recently edited a book titled "Innovation in construction - A Practical Guide to Transforming the Construction Industry". He is a Member of the EPSRC Peer Review College and has been appointed as an expert evaluator for the Dutch Research Council (NWO), the Cyprus Research and Innovation Foundation (RIF), and the Science Foundation Ireland (SFI). Dr Ghaffar has also acted as an expert evaluator on Horizon Europe HORIZON-CL4-2021-TWIN-TRANSITION-01-12: Breakthrough technologies supporting technological sovereignty in construction (RIA) (November 2021) and HORIZON-CL4-2022-RESILIENCE-01-16: Building and renovating by exploiting advanced materials for energy and resources efficient management (IA) (April 2022).  During his PhD (2012-2016), Dr Ghaffar was simultaneously working as a research associate on several European research projects, i.e. Grow2Build, VIP4ALL, REWOBIOREF and GELCLAD. Natural fibre composite production, formulation and characterisation are part of Dr Ghaffar's research expertise. In 2015, he was appointed Manager of Grow2Build European Centre of Excellence (Grow2Build), which serves as a permanent focal point for local manufacturers, industries and research centres interested in bio-based building products, providing technical support and innovation for the utilisation of bio-based products in the construction industry. Moreover, construction waste management and valorisation (WasteValue) is another of Dr Ghaffar's research interests. This research aims to study the feasibility of the circular economy (cradle to cradle) management of waste and the environmental sustainability of the systems in construction. WasteValue evaluates and analyses current technologies and strategies concerning construction and demolition waste management in the UK.

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Project last modified 27/01/2022