Blood enzyme could hold key for self-healing concrete

In Massachusetts, researchers at  Worcester Polytechnic Institute have developed a promising technology for self-repairing concrete. The breakthrough could help cut down on the enormous amount of carbon emissions attributed to construction and infrastructure industries. 

The key ingredient is carbonic anhydrase, an enzyme that transports CO₂ out of human blood so it can be exhaled. 

“Concrete production and repair and transport is a very, very, energy-intensive problem,” says Nima Rahbar, an associate professor of civil and environmental engineering at Worcester Polytechnic Institute.  Nearly a tenth of all carbon dioxide emissions globally come from concrete. “If you can make concrete that can last longer, so you don’t have to replace it, you can make a dent in this 9% of emissions,” he says. 

The enzyme essentially pulls CO₂ from the atmosphere and forms calcium carbonize crystals that can quickly fill in small cracks—keeping larger cracks that require repair work from forming. 

“We spray a solution that is composed of enzyme, water and calcium,” Rahbar says. “We then can blow CO₂ and fill the cracks in minutes, or use ambient CO₂ that will take longer to heal the cracks.”