Wahington State University researchers have developed an alternative to traditional concrete using coal fly flash. This provides a solution for two major problems in the United States.
The first one is the environmental impact of concrete production. Nowadays, concrete is made by combining cement with sand and gravel. Cement requires high temperatures to be produced. Therefore, an enormous amount of energy is used for this. The whole process produces between five and eight percent of the greenhouse gas emissions worldwide.
Another problem is the coal fly. It is a waste product of coal-based electricity generation. And there is a huge issue with managing it in the United States: more than 50 percent of it ends up in landfills and easily leaches into the nearby environment.
The solution for these two problems was developed by Xianming Shi, associate professor at WSU’s Department of Civil and Environmental Engineering, and graduate student Gang Xu. They found a way to create an alternative for cement that does not require heating at all and uses the fly ash.
Some researchers tried to use fly ash in concrete in the past, but they did not succeed in eliminating the intense heating methods.
Shi and Xu engineered concrete at a molecular level using nano-sized materials. They used graphene oxide to manipulate the reaction of fly ash with water and turn the activated fly ash into a strong cement-like material. The final product was even more durable than hydrated cement.
Additionally, it is pervious so water can pass through it. This characteristic helps to replenish groundwater and to mitigate the flooding potential.
The researchers have demonstrated the strength and behavior of the material under a variety of load and temperature conditions. Infiltration tests and gathering data using sensors under the concrete are still being conducted.
IN order to prove the concept, they would like to build some structures with this material. Eventually, they hope to commercialize the patented technology.