From a Climate Problem to a CO₂ Storage Solution? Rethinking Concrete
From a Climate Problem to a CO₂ Storage Solution? Rethinking Concrete
Concrete is the most important building material in our modern society—and at the same time, a major challenge for climate protection. The production of cement, in particular, causes significant CO₂ emissions.
But old concrete, of all things, could become part of the solution in the future.
Researchers are working on processes in which demolition concrete is not only recycled but also permanently sequesters CO₂. Through a process known as mineralization or carbonation, carbon dioxide reacts with calcium-containing components of the concrete and is converted into stable mineral compounds.
Demolition concrete could thus become both a new raw material and a CO₂ storage medium.
CO₂ becomes a component of the material
The principle is based on a natural chemical reaction.
Concrete slowly absorbs CO₂ from the environment even during its normal service life. However, new processes are designed to significantly accelerate this process in a targeted manner.
Old concrete is particularly interesting in this context.
After buildings are demolished, the concrete is crushed. This creates very large new surfaces. If these materials are treated with CO₂ under controlled conditions, some of the carbon dioxide can react with the material and be permanently bound as calcium carbonate.
This not only stores the CO₂ in the short term, but also chemically converts it into a solid mineral state.
New research highlights the potential
In July 2026, researchers investigated how fine powders derived from construction and demolition waste could be specifically used for CO₂ mineralization.
The results show a measurable storage potential: Depending on the material , recycled concrete powder was able to permanently sequester between 33.5 and 54.7 kilograms of CO₂ per metric ton of material.
Another study published in August examined carbonated fine and coarse recycled aggregates for use in new concrete. The study addresses not only CO₂ sequestration but also a crucial practical question: Can the recycled material subsequently be reused to produce high-quality concrete?
Research shows that CO₂-treated recycled materials can generally be reincorporated into new concrete mixtures.
This creates a cycle in the long run:
Buildings – Demolition – Recycling – CO₂ Mineralization – New Concrete.
Europe is also investing in the technology
Several research programs on the next generation of climate-friendly building materials are already underway in Europe.
In the EU-funded C-SINC project, researchers and companies from several European countries are working on novel binding agents. The goal is to use magnesium silicates to permanently bind CO₂ in mineral form.
The goal goes well beyond traditional recycling: The aim is to replace some of the conventional cement with materials that absorb CO₂ during their production.
The project is receiving approximately 4 million euros in funding.
At the Karlsruhe Institute of Technology, too, such concrete components are already being tested for load-bearing capacity, durability, and safety.
Why Cement Is the Real Problem
Concrete consists mainly of sand, gravel, water, and cement. Cement, in particular, poses a problem in terms of climate impact.
In the production of cement clinker, limestone is heated to very high temperatures. This process generates emissions not only from the energy required.
A significant portion of the CO₂ is produced directly as a result of the chemical conversion of limestone.
That is why the problem cannot be solved simply by powering cement plants with renewable energy.
New binding agents, less cement per cubic meter of concrete, recycling, and CO₂ mineralization must all work together.
Not a miracle cure—but it has enormous potential
That is why concrete does not automatically become a climate-neutral building material.
A recent scientific study from July 2026 even warns against overestimating the natural CO₂ absorption of existing concrete structures. It is nowhere near enough to offset the emissions from cement production.
That is precisely why technical processes that specifically accelerate mineralization while simultaneously producing recycled material for new building materials are of interest.
The key question now is whether these processes can be implemented economically and on an industrial scale.
CO₂ Mineralization & Recycling
Perhaps the most exciting development in concrete is not taking place on construction sites right now, but rather at the end of its current life cycle.
In the future, old concrete could become a valuable raw material that simultaneously permanently binds a portion of CO₂ in mineral form.
This would provide at least a partial solution to two problems—large amounts of construction waste and high CO₂ emissions.
Much of this is still in the research and development phase. But if CO₂ mineralization, recycling, and new binding agents become industrially scalable, one of the world’s oldest and most important building materials could undergo a fundamental transformation.
How can old concrete permanently store CO₂ using new recycling processes?
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