New carbon-negative building material could one day replace concrete

US researchers have developed Enzymatic Structural Material (ESM), a carbon-negative alternative to concrete that turns carbon dioxide into a solid structural asset. 

Strong and cost-effective, this new material is a viable green replacement for conventional concrete.

Developed by a team led by Nima Rahbar at Worcester Polytechnic Institute, ESM could replace traditional building materials in applications such as wall bricks and roof decks.

Unlike conventional concrete, which takes 28 days to cure, ESM can be molded into structures within hours, making it highly suitable for mass production.

“What our team has developed is a practical, scalable alternative that doesn’t just reduce emissions – it actually captures carbon,” Rahbar, the senior author, stated. 

Use of enzyme

Concrete production is harmful to the environment. It is the most widely used man-made material on Earth, yet its production is responsible for 8 percent of global CO2 emissions.

If you treated the global cement industry as a nation, it would be third for carbon emissions, falling just behind the world’s two largest economies (the US and China).

But a team of researchers at WPI has found an unlikely ally in the fight against climate change: a tiny enzyme.

The magic ingredient in ESM is carbonic anhydrase, an enzyme found in human red blood cells that helps us exhale carbon dioxide. Specifically, it speeds up the process of turning carbon dioxide and water into carbonic acid and its essential building blocks in the human body. 

In the lab, this same enzyme accelerates the reaction between water and carbon dioxide. 

This process rapidly generates carbonic acid, which, when introduced to calcium, triggers the formation of solid calcite crystals. 

These crystals act as a natural mineral glue, binding together a structural matrix of sand and carbon to create a durable, rock-like material. 

By mimicking the way nature builds seashells and reefs, this method effectively “traps” greenhouse gases within a solid, usable building block.

Instead of baking limestone in massive, fossil-fuel-burning kilns at high temperatures, ESM is created under mild, energy-efficient conditions. 

Faster and greener alternative

The numbers are difficult to ignore. Traditional concrete production emits about 727 pounds (330 kg) of carbon per cubic meter. ESM, by contrast, sequesters 13.4 pounds (6.1 kg).

The speed of the process is equally disruptive. Conventional concrete requires a 28-day curing period to reach its full strength. ESM can be molded into structural forms within hours.

Moreover, ESM is a high-performance material that withstands the rigors of modern construction. 

It has an average compressive strength of 25.8 MPa, comfortably exceeding the minimum requirements for structural concrete. 

While standard concrete requires intense heat and long wait times to reach this level of durability, ESM achieves its strength under mild temperatures, significantly cutting both energy and labor costs. 

Furthermore, the material remains stable and durable even when exposed to water, making it a viable, long-lasting alternative for real-world infrastructure.

“If even a fraction of global construction shifts toward carbon-negative materials like ESM, the impact could be enormous,” said Rahbar.

The road to the local hardware store is still long. Researchers are now looking to scale up production and further enhance the material’s strength for heavy-duty skyscrapers.

“Future work will focus on improving mechanical properties, large-scale production, durability, and ecological efficiency. Continued development may enable reinforced and functional structural applications while maintaining or further reducing CO2 emissions,” the study concluded. 

The findings were published in the journal Matter.