Engineers from Rice University developed a composite binder using byproduct of coal-fired power plants, which has ability to replace Portland cement in concrete
Concrete production account for largest sources of carbon dioxide emissions worldwide, followed by transportation and energy. Various research organizations are focused on developing eco-friendly and sustainable building material. New composite binder developed by researchers from Rice University has ability to completely replace cement along with reducing waste from power plants at the same time. The study was published in Journal of the American Ceramics Society in June 2018.
Burning of coal in power plant generates fly ash as by product, which is captured and recycled or landfilled. Majority of the recycled fly ash can be used to build concrete, as binders based on waste material do not require high-temperature and energy-intensive processing. Furthermore, this process reduces the emissions generated during concrete production and can make the resulting concrete stronger and more resistant to corrosion.
Researchers determined the most effective mixing strategies for new composite, which allowed them to settle on an optimal balance of about 80% fly ash, five percent of a sodium-based activator, and the rest made up of nanosilica and calcium oxide. The mixture is completely free of Portland cement. The new fly ash binder was found to have compressive strength of 16.18 MPa, which is comparable to conventional concrete made with Portland cement after seven days. While these early results are promising for a more environmentally friendly concrete that’s just as strong as the regular stuff, the team says it plans to further investigate the properties of the new material, including its long-term behavior, shrinkage and durability.