Washington State University researchers have attempted to find a solution to the problem of fly ash, a waste product of coal-based electricity generation and a known environmental and waste management issue. Xianming Shi, associate professor in WSU's Department of Civil and Environmental Engineering, and graduate student Gang Xu, have used graphene in their new method that makes use of fly ash for the production of concrete.

The durable new concrete eliminates the use of cement, which is known to be harmful to the environment. Instead of cement, the fly ash is used as a binder in the concrete. By doing this, Shi and Xu are able to tackle two environmental issues with one solution.

Traditionally, concrete is processed by mixing cement with sand and gravel, which contributes anywhere from five to eight percent of greenhouse gas emissions worldwide. Cement is the key ingredient in concrete and to produce it requires extremely high temperatures and a massive amount of energy.

Some researchers have attempted to use fly ash in concrete production but haven't been able to eliminate the intense heating step involved in creating cement. "Our production method does not require heating or the use of any cement," said Xu.

In order to activate the fly and turn it into a cement-like material capable of binding the concrete, the team used graphene oxide and combined it with the fly ash and water. The combination creates a chemical reaction which rearranges the atoms in the solution, creating strongly bonded atoms in a durable, cement-like binder.

Shi and Xu designed the fly ash concrete to be pervious, meaning that water is able to pass through it. This has the benefit of replenishing groundwater as well as lower potential for flooding.