Researchers used coal waste and created sustainable concrete that will reduce energy demand and greenhouse gas emissions, according to a study published on July 12, 2018.
The study was conducted by the researchers at the Washington State University. This development will be able to tackle two major environmental problems at the same time by utilizing coal production waste and largely reducing the environmental impacts of concrete production. Researchers developed a strong, durable concrete, which comprises fly ash as a binder. Also, the use of cement is eliminated in this process.
5-8% of greenhouse gas emissions across the world are contributed by the production of traditional concrete, as the major ingredient in concrete requires high temperatures and high amount of energy for the production purposes. Moreover, fly ash, which is left over after burning of coal dust has now become a significant waste management issue in the U.S. The use of fly ash in concrete was not successful in certain studies, as the need for intense heating methods could not be eliminated in those studies. However, this research does not require intense heating methods.
Another significance of this study is that nano-sized materials have been used by the researchers to engineer concrete at the molecular level. Graphene oxide was used for manipulating the reaction of fly ash with water and turning the activated fly ash into a strong cement-like material. The graphene oxide rearranges atoms and molecules in a solution of fly ash and chemical activators such as sodium silicate and calcium oxide. The process creates a calcium-aluminate-silicate-hydrate molecule chain with strongly bonded atoms that form an inorganic polymer network more durable than cement.
Moreover, the newly designed fly ash concrete was pervious, thereby allowing water to pass through it to replenish groundwater and to mitigate flooding potential. Furthermore, in the WSU campus test plots, the strength and behavior of the material were demonstrated by the researchers by varying the load and temperature conditions. Further infiltration tests and collection of data using sensors buried under the concrete are being conducted by the research team, hoping to soon commercialize the patented technology.