PBC Today: Concrete matters: How low carbon cement could bridge our public infrastructure gaps

The following article was originally published in PBC Today, and is reprinted here.

David Hughes, chief scientific officer at Material Evolution, discusses the impact low carbon cement could have on our built environment, its future application and its journey within a growing economy of scale.

Rebuild and reuse philosophies are nothing new within construction. For several years now, the reuse of materials, whether foundational building blocks such as steel, or groundwork such as soil, have been discussed and implemented within commercial and public redevelopment initiatives across the country.

At government level, a green redevelopment rhetoric has been evident in the reuse of brownfield sites, helping reduce the carbon impact of building anew amid an increasing struggle for land development space.

We’ve also become accustomed to more sustainable models of heating and lighting in our homes and offices, as well as the material choices within them, to ensure each new property or building created has a minimal carbon footprint.

However, with concrete still making up a large proportion of built environment projects and its foundations, the net zero task ahead remains fraught unless solutions to its decarbonisation can be adopted en masse.

Statistics matter

More than 90m tonnes of concrete are used in the UK to build bridges, houses, office blocks, roads and much more every year. The vast majority of this is made from Ordinary Portland Cement (OPC), which has been a construction industry staple for more than 100 years. Versatile, strong and durable, its qualities are renowned, yet its impact on rising CO₂ emissions is only now becoming more apparent as we accelerate forward on the collective net zero journey.

As the most widely used man-made material in existence, studies have revealed that just one kilogram of cement sends one kilogram of CO2 into the atmosphere. Businesses, like ourselves, are working hard to deliver solutions that could have a transformative impact on statistics such as these, with low carbon solutions that help to reverse negative trends, transform our built environment, and at the same time, build new sustainable supply chains for the construction industry.

At present, trials and uses of low carbon cement have taken place in various guises across the country. In 2020, a low carbon cement was implemented within HS2, which resulted in a reported 42% reduction in CO₂ compared to OPC. The use was a landmark development for the industry, particularly within such a high-profile project that could help influence industry minds for widespread adoption.

While in principle, the use of low carbon cement is the ideal substitute for replacing an archaic and outdated material, there are many obstacles ahead that need to be navigated.

More companies with a mission to reduce carbon emissions and have a positive impact on the built environment need to be born, as cement isn’t the only material that requires attention if we’re to achieve net zero. Contractors, architects and other specifiers will also need to buy in, but the most powerful change must come from government officials.

The upcoming budget is a prime opportunity for the government to mandate the use of lower carbon concretes in line with BS8500 within not just flagship projects, but in our everyday schools, roads, houses, hospitals, and much more.

Public redevelopment

In application, the precast market is where we see low carbon cement having its biggest impact. Twinned with a government rhetoric to hit key housebuilding targets, it’s quite easy to see how building facades, walls, columns, beams, stairs, and flooring could be some of the first steps taken in the product market.

Public infrastructure spaces are also rife for redevelopment opportunity, with parks, town squares, kerbing, blocks, benches, pathways, and more all helping to create clean sustainable spaces within our cities.

As we push to more renewable energy sources, the twinned green philosophies of wind farms and hydrogen plants created with low carbon cement is also an appropriate fit for governments looking to invest in our future. Many low carbon cements, like ours, rely on reutilising industrial waste material to enable its production, so there is further circularity for industry minds to consider and help push forward low carbon cements for industry certification.

Ultimately, building and developing low carbon cement is about economies of scale. The more people that buy into it, the greater its usage (and influence) becomes. But this cannot be achieved in isolation. We need greater collaboration across all elements of the industry to enable the drive to low carbon cement to reach its full potential, and deliver a greener, more profitable future for all.