Research underway to transform carbon dioxide into construction materials
Carbon-recycling technologies make effective use of CO2 emissions captured from steel mills, power plants, cement manufacturing plants, and other facilities to create value-added products. They are being developed as a means to help address climate change. Having recognized their potential, MC is working on those that inject CO2 into concrete, where it becomes mineralized and permanently embedded. Concrete is an essential material for civil engineering and construction projects, and its global market is growing.
Most of the current carbon-recycling technologies are mainly used for a limited scope of unreinforced concrete, such as concrete blocks, so the challenge now is to enhance their mineralization capabilities and broaden their applications.
A proposal by Mitsubishi Corporation (MC) for researching and developing new ways to use CO2 in the production of concrete has been selected for the NEDO1 grant project that encompasses technological developments in the areas of carbon recycling.
This joint endeavour between MC, Kajima Corporation, and Chugoku Electric Power Co.,Inc. aims to improve these technologies so that they can also be applied to the reinforced and cast-in-place concretes used in building construction. MC has already been involved in the development of concrete projects that take advantage of carbon-recycling, including a zero-emission, ecological concrete called CO2-SUICOM2.
In the US, a University of California, Los Angeles (UCLA) research team has received a two-year, $2 million grant from the U.S. Department of Energy to support development of a process that can convert carbon dioxide emissions into construction materials.
That grant, and an additional $905,000 in new funding from UCLA discretionary funds and industry partners, will advance research led by Gaurav Sant, a professor of civil and environmental engineering and of materials science and engineering at the UCLA Samueli School of Engineering. A team headed by Sant invented CO2Concrete, a form of concrete that is made in part from carbon dioxide emissions, which are an underlying cause of climate change.
The technology they devised captures carbon dioxide from raw flue gas as it exits power plants, cement plants and other producers of carbon dioxide, reducing emissions to the atmosphere. The process also cuts down on the use of traditional cement, the binding agent in concrete. Since the system developed by Sant’s team captures carbon dioxide directly from raw flue gas, it eliminates the high cost of carbon dioxide capture.
Sant said the product will have a carbon footprint 50% to 70% lower than that of regular concrete used in construction. The production of cement results in more than 8% of annual man-made carbon dioxide emissions. The technology for producing CO2Concrete is being demonstrated at the Wyoming Integrated Test Center at the Dry Fork Station in Gillette, Wyoming.