Concrete is the backbone of modern construction – strong, widely available, and cost-effective. But unfortunately, the cracks in concrete’s sustainability scores have been showing for some time…
Fresh concrete is an environmental heavyweight. Each year, the UK alone consumes around 90 million tonnes of concrete. Globally, concrete production contributes to a staggering 8% of carbon emissions. And the process isn’t just carbon-intensive; it guzzles water, drains natural resources, and demands massive amounts of energy.
The good news is that recycled concrete is changing the game. Just one tonne of recycled concrete can slash 900kg of CO2 and save 6,182 litres of water.
But how exactly does concrete recycling work, and what are the best ways to maximise its benefits?
The benefits of using recycled concrete
Concrete production is also one of the biggest contributors to global carbon emissions—but recycling concrete flips the script. Processing old concrete requires far less energy than manufacturing it from scratch, cutting greenhouse gas emissions significantly.
Recycling concrete reduces dependency on natural raw materials. By breaking down used concrete, the valuable material can be repurposed for new builds, road bases, subbases, backfill, pipe bedding, and even new concrete production.
This shift not only preserves resources but also reduces the strain on ecosystems disrupted by quarrying and mining operations.
And recycling concrete isn’t just good for the planet – it’s good for your bottom line. By repurposing aggregates from demolition projects, construction companies gain access to high-quality, cost-effective resources, cutting expenses on material acquisition.
With more recycled materials available locally, transport costs drop, and fuel emissions from hauling fresh materials are significantly reduced.
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Deconstruction: Supporting the future of recycled concrete
While demolition is often the go-to method for pulling down old structures, deconstruction is the more sustainable choice. Instead of bulldozing everything into rubble, deconstruction carefully dismantles structures, preserving valuable materials for reuse.
For example, SunDemolition works with contractors and developers to identify reusable concrete elements early, from precast panels to large structural slabs. Where full reuse isn’t viable, we cut sections down for secondary use, minimising the need for energy-intensive recycling processes.
Modular construction methods take this even further. By designing buildings with future reuse in mind, large sections of concrete can be directly repurposed, eliminating the need for crushing and processing altogether. Even when modular design isn’t possible, existing slabs can still be cut to size and reused.
The benefits are enormous. Every cubic metre of reused concrete saves over 250kg of CO2 compared to casting new.
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Of course, not all concrete can be easily reused onsite, but that doesn’t mean it can’t be reintroduced into the construction circular economy.
The concrete recycling process
Piles of demolished concrete and debris might seem like a lost cause, but at SunAggregates, it’s just the beginning of something new.
Once concrete arrives at our Thetford site, it enters a carefully controlled process designed to recover, refine, and repurpose into new materials, including recycled stone and fill sand.
Step 1
The process starts with large chunks of recovered concrete, which are crushed down into smaller, manageable pieces using heavy-duty machinery.
Step 2
This crushed material then enters a multi-stage wash and separation process. At SunAggregates, the state-of-the-art UltraSCRUB system uses high-pressure cleaning, screening, and water-based separation to strip out impurities and separate materials by size.
Step 3
Final processing refines and tests aggregates to ensure they meet industry standards.
The results are fine and coarse aggregates that replace virgin sand and gravel for use in new concrete (aggregates make up around two-thirds of concrete and asphalt; the rest is cement and water).
And as technology develops, even more value is being extracted from recycled concrete.
RELATED: New SunAggregates wash plant opens in Thetford
The latest innovations in concrete recycling
Leading researchers from around the world are developing cutting-edge methods to make concrete fully recyclable.
SINTEF’s RECONC project is revolutionising construction recycling with a new technology that extracts the cement from old concrete for reuse. “It’s potentially possible to recycle everything, but it takes a while to get everyone in the right mindset”, argues Chief Research Scientist Christian John Engelsen.
Meanwhile, commercial companies in Norway are looking into dry washing cement trucks to get recycled concrete slurries, which would cut water used in current processes by up to 90%.
Researchers at the University of Cambridge made a pivotal discovery by successfully recycling old cement from demolition waste. The process piggybacks the electric-powered furnaces that recycle steel by adding reclaimed cement powder instead of lime flux. At the end of the steel recycling process, it produces a cement clinker as a bi-product, virtually identical to that used in new Portland cement, without the carbon footprint of traditional cement production.
This could be a huge breakthrough for the construction industry—potentially leading to the world’s first zero-emissions cement.
RELATED: Sustainable building materials: Is this the end of concrete?
The first building made entirely of 100% recycled concrete
While many construction projects use at least some recycled concrete these days, Holcim has taken it to the next level. The construction materials giant has developed the world’s first 100% recycled cement clinker, paving the way for fully recycled concrete buildings.
Cement clinker is the primary ingredient in cement, produced by heating raw materials, typically quarried limestone, at incredibly high temperatures. Holcim’s breakthrough trial replaced those new resources with a selection of 100% recycled materials, ranging from wood ash to mineral processing waste.
Their pilot project—a 220-unit social housing complex near Paris—was built entirely with recycled aggregates, cement, and water. By reusing over 6,000 tonnes of materials, the project proved that a truly circular construction industry is not just an idea, it’s happening!
Recycled concrete is no longer a compromise; it’s a smarter way forward. From careful deconstruction to precision processing, it’s time for the construction industry to see the real value of what’s already in our hands. With every slab saved and every tonne recycled, we move closer to a truly circular economy—one where yesterday’s buildings really do become tomorrow’s foundations.
SunAggregates supplies a range of construction materials recovered through its concrete recycling process. All aggregates are sustainable, high quality, and comply with BS EN 933-1 standards. Contact our friendly team of experts to discuss how we can make your next construction project more eco-friendly.
