In July, the new government announced plans to build 1.5m new homes by 2029 to meet the increasing demand for housing. It also committed to making it easier to build key infrastructure such as laboratories, gigafactories and data centres by overhauling the planning system. While these initiatives promise to address the housing crisis and support economic growth, they also come at a significant cost to the climate.
The construction industry accounts for about 14% of the UK’s total emissions and concrete is the main culprit. In fact, it's responsible for a staggering 8% of global carbon emissions. This is primarily due to the production of cement - the key binding material in concrete.
To meet the legally binding target of achieving net zero emissions by 2050, the UK must find a way to balance its housing and infrastructure ambitions with its environmental goals. However, government strategies like the 2025 Future Homes Standard and its recent report on Housing and Net Zero, ignore the importance of concrete to construction and, consequently, the impact this has on the emissions from new homes. Thankfully there are innovative solutions to address the carbon cost of concrete that don’t require overhauling the construction industry or planning regulations.
Mineralising CO2 and recycling concrete
The concrete industry is responsible for the emission of 3 billion tonnes of CO2 a year and with today’s manufacturing processes, the vast majority of these emissions are released straight into the atmosphere.
One of the most promising technologies that can address this is the mineralisation of carbon dioxide in concrete. This process sequesters CO2 during concrete production using a carrier injected with captured carbon, typically from the process of cement manufacturing where CO2 is emitted.
When done correctly, this improves the mechanical properties of concrete, making it stronger so less cement is needed to produce concrete. This can lock away carbon permanently while also helping to reduce emissions from existing manufacturing processes. It also integrates with existing production lines making it easy to scale in a short time frame.
The key to success, however, lies in the method and amount of CO2 sequestration. New methods of controlled mineralisation can enhance strength and performance while reducing the need for cement by up to 15%, but previously excessive carbonation compromised the durability of mineralised concrete.
Another emerging trend is the recycling and upcycling of end-of-life concrete. Separating cement from aggregates in old concrete structures can create new types of binders which can be reused in construction. While this approach shows great potential, it is costly and faces significant challenges in scaling and establishing efficient supply chains. However, as landfill space becomes scarce and circular economy principles gain traction, this method could become a key component of sustainable concrete production.
A complementary approach
Carbon mineralisation and concrete recycling can be especially impactful as they address myriad challenges the construction industry is facing, including supply chain issues and the knock-on effect of other climate-change policies.
Historically, the concrete industry reduced its emissions by substituting cement with supplementary cementitious materials (SCMs) like fly ash and granulated blast furnace slag (GBFS). These materials, by-products of coal combustion and steel production, offered a way to reduce the reliance on traditional cement. But, in the UK and elsewhere, coal-fired power stations are being phased out with the EU targeting an 83% reduction in coal-generated electricity by 2030. As a result, there is a growing shortage of SCMs. As more steel producers transition to electric arc furnace technology, the availability of GBFS is also diminishing.
Carbon mineralisation reduces the reliance on SCMs and GBFS, so its wide scale adoption would remove the need to import these materials without impacting the availability of crucial construction materials. It presents a circular approach by which the cement and concrete industry can utilise the CO2 it produces within concrete to permanently remove CO2 and meaningfully reduce embodied carbon.
While the government’s strategy to decarbonise homes under the Future Homes Standard is a step in the right direction, it is largely focused on reducing emissions from homes that are already built. Adopting more climate-friendly approaches in the build stage would enable a sustainable end-to-end approach from construction to maintenance. This would be a more holistic and effective approach which complements the government’s other efforts to decarbonise homes.
The path to net zero
The road to achieving net-zero emissions in the concrete industry will likely take 15 to 20 years. However, innovative solutions like CO2 mineralisation and recycled concrete can help make immediate progress. For example, these solutions could first be applied to non-structural components, allowing the industry to test and refine the technologies without disrupting existing supply chains and avoiding lengthy regulatory approvals.
Policy support is also crucial to encourage faster adoption of low-carbon solutions. Incentives, such as government subsidies for early adopters, could help bridge the gap between innovation and commercial viability. Over time, as new technologies are adopted and economies of scale reduce costs, these innovations will become more widely accessible.
In the longer term, advancements in novel cementitious materials, kiln technology, and alternative fuels could further reduce the industry's carbon footprint. However, achieving meaningful change will require a collaborative effort across the entire value chain, including manufacturers, policymakers, investors, and end users.
The UK’s targets are ambitious, and there is an urgent need for new homes and infrastructure fit for a rapidly developing world. But this must be balanced with the equally pressing need to address the construction sector’s environmental impact. The key to low-carbon construction is the right mix of innovation, investment, and policy support.
Dalraj Nijjar is co-founder and CCO of Concrete4Change
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