Two firms in Boston have just laid the foundations of a large building using a USA-made zero-carbon cement mixture, representing one of the first adoptions of this technology in the real world.

Many companies are testing or subsidizing low/zero carbon cement and concrete hoping to reduce their carbon footprint, but few as yet are using it liberally to build real structures.

Manufactured by Sublime Systems, which was just named to Fast Company Magazine's Most Innovative Companies in Sustainability for 2024, the firm uses an electrochemical process to create the cement for ready-mix products.

At the heart of traditional Portland and other kinds of cement is its heating in a kiln wherein calcium carbonate reacts with silica-bearing minerals to form a mixture of calcium silicates. Over a billion tonnes of cement are made per year, and cement kilns are the heart of this production process: heating the mixture to over 1,300°C and producing around 5% of all made-made carbon emissions worldwide, according to The Economist.

By eliminating the kiln altogether, Sublime Systems has removed the large majority of emissions from the process.

Best of all, it's actually being used right now in the Greater Boston Area. Boston Sand & Gravel is supplying Turner Construction Co. with ready-mix cement containing Sublime Systems' product to form the mud mat of a large building.

"It's going to be in that building for decades to come," Leah Ellis, Sublime Systems' CEO, told Engineering News Record.

"It really was the culmination of a lot of effort to see it not just being done for testing's sake, but actually, replacing cement that would otherwise have been the carbon-intensive variety."

Along with reducing the carbon emissions budget of that new building, the construction has validated that several key targets of Sublime Systems' product have been met: the product was transported to the site in a ready-mix concrete truck like normal, maintained malleability during transit, was poured out of the concrete truck and into a hose, and the hose was able to deliver it to the setting where it stuck and hardened-all exactly like traditional cement.

"In the grand scheme of things, it was, really, very boring for construction," David Robb, a Turner estimator and the preconstruction manager on the Boston-area project, told ENR. "But it's it's a huge step in terms of our embodied carbon reduction goals that we're striving toward in the future here at Turner."

Government money as well as private investment has been pouring into Sublime Systems' which seems poised to lead a great revolution in cement by building its first full-scale, dedicated manufacturing facility in Holyoke, Mass.

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