Decarbonising construction today with low carbon concrete
Credit: Mineral Products Association
The UK construction sector, working in collaboration with UK manufacturers of cement and concrete, has a strong track record of reducing emissions from concrete construction. But there are opportunities to accelerate the adoption of new low carbon concretes and reduce the carbon emissions of our built environment even further.
Britain already has a good track record of reducing emissions from cement and concrete, with the sector’s absolute CO2 emissions already 53% lower than they were in 1990. But there is potential to go even further.
Government is supporting industry to develop new, lower carbon concretes and cements. Both the public and private sectors can act now by increasing the uptake of already available low-carbon concretes and cements.
Concrete is a mix of materials, including cement (of which there are many different types) and aggregates. Not all concretes are the same, and different mixes will have different performance characteristics, can be used for different purposes. They will have different values of embodied carbon as a result.
Reducing the embodied carbon of cement is one way to help decarbonise concrete. The Mineral Products Association (MPA) has led research, supported by industry and BEIS, which successfully developed and trialled new low-carbon cements with embodied emissions up to 60% lower than the current market leader – CEM I.
CEM I or Portland cement consists mainly of a material called clinker. The cements tested in this research are part of a growing cohort of ‘multi-component cements’, which substitute some of the clinker for alternative materials with a smaller carbon footprint. The new low carbon cements use a combination of clinker, limestone and either ground granulated blast-furnace slag (a by-product from the manufacture of steel) or fly ash (a by-product from coal-fired power stations). Using these new cements in concrete could reduce carbon emissions by up to four million tonnes a year (compared to concretes using CEM I). The concrete slabs pictured above are part of this trial. Another research project, funded by UKRI and led by MPA, is testing the use of calcined clays in multi-component cements. You can read more detail on our paper on low carbon concretes.
Decarbonising cement and concrete production – and by extension, construction – is a multi-faceted process, and the industry has a roadmap setting out the potential to achieve net zero by 2050, provided it receives the right support and investment from Government. Supporting research and development is a key part of this, but so is encouraging the uptake of low-carbon cements and concretes, which can deliver immediate reductions in emissions.
Ministers can achieve this by ensuring that the public sector specifies UK-produced low-carbon cements and concretes, where appropriate, in its own construction projects. The public sector is a major client of the construction sector, and it can use its considerable purchasing power to increase demand for these materials. In 2021, the Environment Agency made low-carbon concrete their default option for flood defences and other infrastructure projects. Other agencies and Government departments should follow their example.
The Government can foster further innovation in this area to complement driving wider adoption of already-available solutions. Encouraging public sector clients to engage early with concrete manufacturers can not only help the client identify the lowest-carbon concrete available and appropriate for their project; it can also potentially lead to opportunities to support trials of new formulations. National standards should also be developed and modified without unnecessary delay to increase access to low-carbon cements and concretes.
More directly, the Government could set up funding programmes aimed at increasing the number of low-carbon cement formulations accepted under UK concrete standards. Ministers have set up a range of funding schemes to foster innovative low-carbon technologies across a wide range of industries in recent years – extending this to cement and concrete would be an important step forward in decarbonising construction quickly.
Using low-carbon cements and concretes more widely while supporting their further development is an opportunity to save carbon now that the Government must not miss.
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