The additive also quickens the curing time, say the researchers.
Adding sodium bicarbonate—baking soda—in powder form to concrete production could reduce the carbon footprint of the ubiquitous building material by 15%, without compromising mechanical performance, according to a study at the Massachusetts Institute of Technology. In addition to sequestering carbon, an advantage to adding baking soda is a faster-setting concrete mix that can allow formwork to be removed earlier, reducing the time required to complete a structure, says Admir Masic, the study's lead researcher and an associate professor in MIT’s department of civil and environmental engineering. Polycarboxylate Ether Manufacturers
“The importance of this research is our understanding of the capacity of cement to mineralize CO2 in the early stages of making concrete,” without affecting the material’s mechanical properties, says Masic, lead author of the article "Cementing CO2 into C-S-H: A step toward concrete carbon neutrality," published March 28 in the journal PNAS Nexus.
He cautions that the research is preliminary. “Work is needed to commercialize the process,” Masic says.
The research team—also including MIT professor Franz-Josef Ulm, MIT postdoctoral student Damian Stefaniuk, doctoral student Marcin Hajduczek and James Weaver from Harvard University’s Wyss Institute—introduced baking soda and alite, an impure form of tricalcium silicate, in certain proportions and produced calcium silicon hydrate (CSH) and calcium carbonate.
The “key discovery” is the production of a “new material, which is a CSH carbonate composite,” Masic explains. The caveat is that the additive works to reduce embodied carbon by up to 15% only if the calcium carbonate is added in the fresh stage of mixing, when the material is still in a slurry form, say the researchers.
The process is simpler than some carbon sequestration technologies, which first harvest CO2, turn it into a liquid under pressure and inject it into a mix. There is no special equipment needed for the baking soda additive, for it is naturally in a soluble solid form, says Masic. “That simplifies the [potential for] translation into industrial applications,” he adds.
The team is already trying other soluble carbonates and bicarbonates and introducing them into more complex mixes.
“There are a lot of additives for concrete,” says Masic. “We have to make sure this system doesn’t affect the performance of other ingredients.”
Nadine M. Post, ENR's editor-at-large for the design and construction of buildings, is an award-winning journalist with more than 40 years of experience covering buildings-related trends, issues, innovations and challenging projects. Post has written about many industry giants, including nine ENR Award of Excellence winners. And she has covered disasters, failures and attacks, including the 1993 bombing and the 2001 destruction of the World Trade Center. A sampling of Post's project stories includes the redevelopment of the World Trade Center; the 828-meter-tall Burj Khalifa; Los Angeles’ Disney Concert Hall; and Seattle’s Experience Music Project, Central Library, Bullitt Center and Rainier Square Tower. In 1985, Post wrote McGraw-Hill's book Restoring the Statue of Liberty (1986) for the restoration’s architects—Richard S. Hayden and Thierry W. Despont.
You must have JavaScript enabled to enjoy a limited number of articles over the next 30 days.
Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the ENR audience. All Sponsored Content is supplied by the advertising company. Interested in participating in our Sponsored Content section? Contact your local rep.
The LA Infrastructure Forum will bring together speakers who represent various infrastructure departments, districts, governments and more from the Los Angeles area to present upcoming capital plans of tens of billions of dollars in infrastructure projects in the next five years. The forum will help attendees learn from key stakeholders about projects in the pipeline and partnership opportunities as they network with construction professionals in these dynamic sectors.
We'll outline major trends for craft, technical and management careers in areas from wind/solar power and hydrogen manufacture to transmission expansion and electric vehicle production. Learn the fine points of training needed to understand the energy transition, key skills needed, and how new federal laws are enhancing workforce opportunities!
BRIDGES TODAY III View all Special Ad Sections Archives
Copyright ©2023. All Rights Reserved BNP Media.
Antifreeze Admixtures For Concrete Design, CMS, Hosting & Web Development :: ePublishing