Concrete is evolving beyond its grey reputation
Concrete is everywhere: from roads, to skyscrapers, to the foundations of the building you may be reading this in. It is the most used material in the world with 150 tons used every second worldwide – that’s about 14 trillion meters cubed per year!
Concrete is a composite material, mostly made from sand, gravel, cement, and water.
Cement, which acts as a sort of binding paste, is usually made from limestone and clay. As concrete is a composite material, its composition can be modulated depending on what it is to be used for and the properties needed. For instance, reinforced concrete uses more cement and less gravel and sand compared to concrete used for pavements.
Concrete fits our society’s needs so well it is hard to believe how old it actually is. The Romans were already using it more than two millennia ago (think: the Roman Pantheon!). Concrete was however significantly improved throughout the 19th century, with inventions such as reinforced concrete in 1849. Today, while concrete and cement are omnipresent in our lives, there are concerns about their environmental impact. Indeed, cement production is responsible for about 7 to 8% of carbon dioxide emissions worldwide because of the calcination process and chemical reactions that happen during processing.
This has led industry to research low-carbon solutions to improve concrete.
In an attempt to reduce the carbon footprint of concrete, Holcim UK looked at replacing clinker – a nodular concrete intermediary which requires high temperatures for production, making it the most carbon-intensive part of the process. They were able to replace 20% of the clinker in Portland Cement by recycled concrete fines, a waste product from demolished buildings. This concrete was tested throughout 2024 and 2025, and the company plans to scale up the project by 2026. Replacing components is a growing field of research. At the University of South Australia, researchers used alum-based water treatment sludge and developed a concrete that is better in terms of corrosion and stress resistance than classic concrete.
Another notable example is a concrete in which cement was replaced by a mix of graphene and limestone to reduce the carbon emissions. This concrete, developed by the Graphene Innovation Centre with Cemex UK, Galliford Try, Sika, and Northumbrian Water, was shortlisted for the 2025 Building Innovation Award in the Best Carbon Reduction Innovation or Practice category.
Steel production also has a significant carbon footprint, so it is no wonder that replacing steel reinforcement with other materials has been looked into. The Austrian startup Fiber Element is using 3D-printed basalt fibre grids instead of steel for reinforced concrete. In addition to being more sustainable, basalt is lighter, stronger, fully recyclable, more durable, will not corrode, and can be used in extreme environments.
To reduce the carbon footprint of the industry, making stronger and more durable concretes and cements is also key. Self-healing concretes might be the way to go for that. The Romans already had self-healing concrete, although that knowledge got lost throughout the centuries and was only recently rediscovered. Roman concrete used lime mortar, and so when a crack would occur and lime chunks would be exposed, they would react with water to heal the cracks. More recently, a team of researchers from Texas A&M University developed a biomimetic self-healing concrete. Using lichen and only needing sun, air, and water, it combines cyanobacteria and fungi to produce minerals that fill the cracks.
Innovation in concrete today is not limited to lowering its carbon footprint; it is also reshaping what the material can do. In the Netherlands, Respyre has developed a concrete capable of growing moss, transforming grey urban surfaces into living infrastructure. Elsewhere, researchers at the Michoacan University of San Nicolás de Hidalgo have created a phosphorescent cement, recognised by the Royal Academy of Engineering, with potential uses in roads, safety signage and public infrastructure. At MIT, the Concrete Sustainability Center has taken a different approach, incorporating nanocarbon particles into cement to make it electrically conductive, paving the way for smart and multifunctional concrete structures.
Concrete has long been associated with durability and permanence, but the next chapter of its history will be defined by innovation. From recycled aggregates to smart concretes with new functionalities, innovation is reshaping how this material is produced and used. As the construction sector faces increasing pressure to reduce its environmental impact, concrete stands at a crossroads offering both one of the greatest challenges and some of the most promising solutions for a more sustainable future.
