Living Concrete Lays Foundation for ‘New Discipline’ in Sustainable Development
This photograph shows green photosynthetic cyanobacteria growing and mineralizing in the sand-hydrogel framework. The living material has similar strength to cement-base mortar. College of Engineering and Applied Science at Colorado University Boulder / EurekAlert!
Cement is a remarkable building material; it’s cheap, durable and readily available. However, its production is a leading source of carbon dioxide emissions, coughing up 2.8 gigatons of emissions every year, as Advanced Science News reported.
While researchers have sought alternative means of production that would make building materials more eco-friendly, they have been unable to recreate cement’s durability. Until now. A team of researchers has created concrete that is alive and can reproduce and capture carbon, according to the The New York Times.
The research team from the University of Colorado Boulder created an entirely new material with minerals that are deposited from cyanobacteria. They published their process yesterday in the journal Matter. Cyanobacteria are common microbes that capture energy through photosynthesis. That process means the plants will absorb carbon dioxide, which is the opposite of the industry standard concrete, which spews massive quantities of greenhouse gasses, as The New York Times reported.
While regular concrete is an unfavorable environment for bacteria, this material has a process based around the bacteria, which enlists its creators to build the concrete and keeps them alive so they can make more later on. Since the process stems from cyanobacteria — the same class of bacteria responsible for a harmful algal bloom — it looks green, as The New York Times reported.
“It really does look like a Frankenstein material,” said Wil Srubar, a structural engineer and the head of the research project, as The New York Times reported. However, the green color fades as the material dries.
The research team says their innovation paves the way for living buildings in the future that can heal their own cracks and purify the air, according to the Daily Mail.
“Microorganisms can be leveraged for multiple purposes in the design of [living building materials], including increasing the rate of manufacturing, imparting mechanical benefit, and sustaining biological function,” said the authors in the study, as Advanced Science News reported.
This new concrete “represents a new and exciting class of low-carbon, designer construction materials,” said Andrea Hamilton, a concrete expert at the University of Strathclyde, in Scotland, as The New York Times reported.
The project was funded by Darpa, the Department of Defense’s research arm. Darpa wanted a fast process for creating a living concrete. The researchers started by putting cyanobacteria in a mixture of sand and nutrients. The bacteria did start to produce a calcium carbonate that cemented the sand particles together, but the process was very slow, according to The New York Times.
It’s a lot like making rice crispy treats where you toughen the marshmallow by adding little bits of hard particles,’ said Srubar, as the Daily Mail reported.
Srubar had the idea to add gelatin to the mixture as a way to strengthen the matrix being built by the cyanobacteria. The gelatin successfully added structure, and it teamed up with the bacteria to help the living concrete grow stronger and faster, as The New York Times reported.
“The first time we made a big structure using this system, we didn’t know if it was going to work, scaling up from this little-bitty thing to this big brick,” said Chelsea Heveran, a former postdoc with the group — now an engineer at Montana State University — and the lead author of the study to The New York Times. “We took it out of the mold and held it — it was a beautiful, bright green and said ‘Darpa’ on the side.” (The mold featured the name of the project’s funder.) “It was the first time we had the scale we were envisioning, and that was really exciting.”
“This is a material platform that sets the stage for brand new exciting materials that can be engineered to interact and respond to their environments,” said Srubar, as the Daily Mail reported. “We’re just scratching the surface and laying the foundation of a new discipline. The sky is the limit.”