New automated process to expedite carbon-neutral cementitious mixture production
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The modern cement industry still relies on a century-old long process that comes with significant environmental costs.
Producing Portland cement, the most commonly used type of cement, involves mining raw materials such as limestone and clay and then heating them in rotary kilns to induce high-temperature oxidation.
This energy-intensive step that releases large amounts of carbon dioxide (CO2) from both fuel combustion and the decomposition of limestone. As a result, cement manufacturing accounts for nearly 8% of global CO2 emissions.
An emerging alternative seeks to turn this problem into an opportunity: creating cement from calcium and magnesium-rich industrial mineral wastes (IMWs) that can react with CO2 captured directly from the air. These materials can be carbonated and polymerized to form carbon-negative cementitious mixtures—a more environmentally friendly option.
UIC Department of Chemical Engineering Professor Meenesh Singh has developed a fast, high-throughput screening process to identify the right chemistry to activate these new mixtures.
His research, published in the American Chemical Society Industrial and Engineering Chemistry Research journal, could help move the industry away from carbon-intensive materials and into a greener future.
Harnessing high-throughput screening
Though IMWs are a greener alternative to Portland, they vary widely in composition depending on their source and time of production. Until now, identifying the right chemistry to activate them into durable, cementitious binders has required extensive testing.
Traditional methods to find the right chemistries rely on standardized ASTM industrial protocols, which require up to 28 days to evaluate mechanical strength—significantly slowing innovations.
But Singh has found a faster way: high-throughput screening, an automated, rapid experimentation process that has previously allowed researchers to test thousands to millions of chemical or biological compounds for activity against targets like proteins or cells.
Usually used in medicine, “High-throughput screening in the cement industry is one of a kind,” Singh said.
Singh and his team’s high-throughput system uses infrared signatures during alkali activation to rapidly predict long-term performance. By correlating early-stage infrared signals with 28-day ASTM mechanical strength protocols, the platform dramatically reduces the time required to evaluate new formulations.
What used to take weeks now takes hours, enabling rapid iteration and optimization of carbon-negative cementitious mixtures.
Using calcium-rich sources such as mineral waste, fly ash from furnaces and coal-fired power plants, and slag from steel companies, Singh and his team are creating cementitious mixtures that will help them guide the right composition and adjust that level of strength to optimize rapid mixture design. These mixtures can then be turned into cement using sand or be used as prefabricated panels for the facades of buildings, for example.
“All of these materials have silica and alumina in them and varying compositions of calcium,” Singh said. “If I have one specific composition, I can do the testing and find the right composition to make cementitious mixtures. The problem with the industrial metal wastes is they always have varying composition because not all the coals carry the same amount of silica.”
The IMWs and other waste are provided by industrial partners, including Lehigh Industries.
Singh’s current work expands on the previous efforts to develop carbon-negative alternatives for Portland cement. His previous work was funded through a grant from the U.S. Department of Energy Harnessing Emissions into Structures Taking Inputs from the Atmosphere program.
Singh acknowledged his co-authors Venkata Yadavalli, UIC Department of Chemical Engineering Post-Doctoral Research Associate Rohit Chauhan and department alumni Prem K. Reddy, Vamsi Vikram Gande, and Rajan Bhawnani, and collaborators University of Wisconsin-Madison Biological Systems Engineering Professor Robert Anex and Civil and Environmental Engineering Associate Professor Bu Wang.