Mark Connelly, Professional Head of Highways, Atkins discusses the importance of the Cement 2 Zero (C2Z) initiative.

As the global economy presses towards a greener future, the construction industry finds itself at the crunch point. The industry's labyrinthine structures, complex supply chains, and long project timelines present formidable obstacles to swift decarbonisation.

One of the most pressing areas for decarbonisation in construction is the production of concrete. Concrete is the second most consumed substance in the world after water, and it is one of the construction industry's largest sources of emissions. Yet the industry often overlooks the environmental impact of concrete production, treating it as an infinite resource. Producing concrete is energy-intensive and emits carbon dioxide as a byproduct. Moreover, insufficient attention is paid to the problem of disposing of concrete at the end of its life cycle - and with so much concrete produced, it’s a weighty issue. 

Decarbonising concrete production

Cement 2 Zero (C2Z) is an initiative to decarbonise concrete production through recycling existing concrete. By recycling old cement from demolished buildings, we can bypass the emissions-heavy calcination process using electric arc furnaces (EAFs) harnessed in steelmaking, Driven by the UK FIRES group, which promotes resource efficiency in construction, C2Z aims to make the industry more aware of the finite nature of our natural resources and demonstrate the viability of recycled concrete.

Producing ‘Electric Cement’, the C2Z development project underscores the need to recycle from existing concrete assets, to spread awareness about reducing consumption, and to demonstrate the structural, regulatory, and economic viability of recycled concrete. Together, this would enable recycled materials to eventually become a primary source of concrete. 

Cementing credentials

The Cement 2 Zero initiative has demonstrated that the chemical composition of recycled material remains robust - much like steel, which is heavily recycled. However, the construction industry imposes stringent specifications on materials, and concrete is no exception. Different categories of concrete and cement are required depending on the application, with differing strength requirements and testing methods. Construction firms, designers, and clients tend to be risk-averse, preferring the tried and tested over the new and innovative. 

To overcome these hurdles, the C2Z project team  are consciously harnessing collaboration from the start. Bringing together the academic prowess of the University of Cambridge, the testing facilities at the Materials Processing Institute, the manufacturing capabilities of CELSA, and the real-world application knowledge of contractors, designers, and suppliers, C2Z pioneers an end-to-end solution, from research through to deployment. This collective, joined-up approach speeds up the pace of change, targeting not only the technical challenge but also the myriad barriers blocking adoption of recycled concrete.  

Scale matters, too. The involvement of Tarmac, a major global supplier, further amplifies the reach and potential impact of C2Z. National Highways has also expressed interest in using a future project to trial the material. Atkins and Balfour Beatty are bringing their collective design and construction expertise to enhance the collaborative nature of the project. It demonstrates how collaboration can disseminate innovation across industry - pioneering faster, more effective change and offering a blueprint for rapid decarbonisation.

Paving the way forward

The pathway to a low-carbon construction industry is paved with collaboration and leadership. The complexity of the sector, its regulations, and its supply chains necessitates a collective approach, with all stakeholders sharing successful practices and innovations. The widespread use of concrete, coupled with its rigorous specifications and standards, means that successful trials can lead to a swift, industry-wide adoption of sustainable alternatives like C2Z. The opportunity is massive. 

But if we’re to exploit it, we also need leadership. Just as board-room commitment to sustainability is essential to a company’s Net Zero efforts, so too is sector leadership vital to driving and disseminating sustainability across industry. Asset owners are now recognising the value in existing concrete assets and in the ability to recycle and repurpose them - and by exploiting these, we can avoid carbon-intensive manufacturing and its drain on natural resources. 

C2Z shows that shared commitment, collaborative cross-sector problem-solving, and enterprising leadership can catalyse solutions and steer the construction industry towards a more sustainable, low-carbon future. We can build the world better - but only by working together.