Potential alternative ingredient for cement

Graphene has been found to offer an alternative as a replacement for sand in concrete as well as a reinforcing additive in cement.

Researchers at Rice University in the US discovered that graphene could be used in place of sand due to sand mining rates outstripping natural replenishment. Metallurgical coke is a coal-based product.

As sand comprises 30% of concrete, it represents a significant part, according to Satish Nagarajaiah, Professor of Civil and Environmental Engineering and Mechanical Engineering.

“The fact that we’re on the brink of a ‘sand crisis’ motivates us to look for alternatives, and metallurgical coke, which costs about the same as sand at about 10% of the cost of concrete, could help not only make better quality concrete, but also eventually translate into significant savings,” he said.

Flash joule heating produces graphene faster and at a larger scale than previous methods. It has the potential to reduce reliance on natural sand and lower carbon emissions in the concrete industry, making the technology more sustainable for urban development.

With almost 70% of the global population expected to live in urban areas in around 25 years, demand for concrete is projected to grow significantly. Consequently, so will sand mining which has tripled since the turn of the century to currently 50 billion tons annually.

While it will take some time for the cost of graphene to be low enough for this to be viable, said the researchers, it shows there are alternatives to pursue.

About the author

Desi Corbett

Desi is our weekly news journalist and the editor of Concrete in Australia magazine for 10 years. She has been heavily involved in all forms of engineering since 2013; part of a 30-year writing career across a range of subjects and media.