In July, about 60 tons of concrete was poured into the dusty basement of a building in Seattle, Washington, as part of a renovation of the historic building. To an outsider, it looked like just a work site. On that day, the workers pouring and shaping the concrete went about their business almost as usual.
Indeed, this messy and decidedly unglamorous event marked a milestone in the race to cut global CO2 emissions by gigatons. That’s because the concrete was made using a more sustainable bonding material developed by startup C-Crete. For Rouzbeh Savary PhD ’11, founder and president of C-Crete, the fact that work proceeded as usual was a huge success. That’s because a seamless, low-cost transition will be needed to clean up construction’s large, conservative industry.
“We’re glad we didn’t start with a flagship building, which only wealthy companies might be able to afford,” Savary explains. “Cement is a very plentiful and very low-cost commodity, so if new products aim to have an impact on CO2 emissions, they need to penetrate a mass market that everyone can relate to and buy. there is.”
Decarbonizing concrete would lead to real and meaningful reductions in greenhouse gas emissions. Although estimates vary, the International Energy Agency has found that the cement industry accounts for about 7% of the world’s anthropogenic CO2 emissions. Concrete is the second most used substance in the world after water. Savary likes to say that even water usage is inflated in its rankings because it is used to make concrete.
C-Crete’s patent-pending material combines locally available mineral raw materials and industrial by-products to produce cement-free concrete. This material can be produced without the high temperatures required to make Portland cement, reducing energy requirements. According to the company, C-Crete’s binder also absorbs CO2 over time, making the material’s lifecycle even greener.
“Our vision is to be able to use the local earth’s crustal composition to produce cementitious binders,” says Savary. “Cement is used everywhere and doesn’t need to be shipped all over the world.”
Now, with what Savary says is the first Portland cement-free concrete pour in the United States in Seattle, C-Crete hopes to leverage widespread interest and partnerships to quickly scale up.
“A single material can have a very large impact,” Savary says. “We aim to reinvent 100-year-old Portland cement using local materials and employ this in construction.”
From $100,000 to products
In the late 2000s, Savary pursued a PhD in MIT’s Department of Civil and Environmental Engineering. But to deepen her understanding of cement, she also took courses in materials science, business, and physics. During his time at MIT, he also joined his newly established MIT Concrete Sustainability Hub.
“Cement science is an interdisciplinary field, so I had to gain knowledge through different disciplines,” says Savary. “That gave me exposure to technologies and startups in different fields. I met several companies that were trying to address problems around composite materials and energy efficiency and learned something from their problems and solutions. , I thought about how I could apply that to my own complex materials.”
At the time, the concept of low-carbon cement was still in its infancy, but Savary nevertheless proposed a low-carbon alternative to the excess material in MIT’s $100,000 Entrepreneurship Competition. Sabally won the contest and was able to pursue the idea further. He founded C-Crete in 2010, his last year at MIT.
“I am grateful to MIT for giving me the opportunity to dream big,” Savary says. “We are not quite where we want to be yet, but we are on a good trajectory. It played a big role in building my confidence to tackle the issue head-on.”
For the next ten years, Savary continued to experiment with material combinations. Now, to make concrete, workers mix Portland cement with water to create a paste that binds to materials such as sand and rock. Cement production is an expensive and carbon-intensive part of concrete, so Sabally wanted to find a set of molecules that could produce a cement-like binder.
“Our lab has identified about 2,000 formulas that probably don’t work,” Savary says. “But every time we failed over the years, we learned a lesson and said, ‘Okay, one more failure.’ It wasn’t completely Edisonian, we had some guidelines, but we were narrowing down our options. ”
The combination of molecules that C-Crete ultimately decided on is still kept secret as the company is waiting to obtain a patent, but third-party testing has confirmed the performance requirements for Portland cement, including strength and fluidity. It was found that it satisfies the
“The industry is used to Portland cement, and the debt associated with construction projects means that contractors and workers will be reluctant to switch if a new product is complicated to use or behaves differently.” Savary says. “We want it to be a drop-in technology that results in minimal or no changes to the current behavior of the concrete, from the dry mix components to the liquid and curing stages. We wanted to make it as easy as possible and as close to traditional practices as possible.”
C-Crete has received strong interest in partnering with companies such as ready-mixed concrete companies that operate trucks with rotating cement containers on the back.
“All they have to do is take our binder and replace it with Portland cement,” Savary says. “The resulting concrete has the same mix design. The ratio of gravel to cement, sand to cement and admixtures is the same.”
Realization of green cement
C-Crete’s current production facility can produce tens of tons of binder per day. A general cement manufacturer can produce more than 2,000 tons per day. But the company plans to scale up quickly by partnering with manufacturers, and Savary has received inquiries from architects, engineers, construction companies, and building owners around the world who want to use C-Crete’s binders. There is.
“More and more people are interested in solving this problem because of concerns about carbon emissions,” Savary said.
C-Crete also continues to innovate when it comes to materials. This month, the U.S. Department of Energy awarded the company $2 million to develop a way to use carbon dioxide captured from the air in concrete, making it carbon negative. In early September, C-Crete received about $1 million more from the ministry to expand the types of materials it can use to make cement-free concrete.
But for now, C-Crete is primarily focused on scaling up production and deployment of its existing technology. Fortunately, Savary believes the industry is beginning to share his sense of urgency on this issue.
“Everything has changed since I was at MIT, when there wasn’t a lot of interest from the market,” Savary says. “We seem to be at an inflection point. We now have a good product and market fit. If we can scale up and execute as planned, we will have a big impact.”
