The modern world’s foundation is built upon concrete. Every building worldwide uses versatile and robust material to give the structure its shape and strength. This ensures that the concrete industry is constantly on the rise. However, the demand comes at a cost: environmental harm. It is reported that the use and manufacturing of cement (the main component for concrete) is responsible for around 7% of the global carbon dioxide emissions. Out of this 7%, a large proportion belongs to the necessary use of calcium within the concrete obtained through the burning of limestone.
A research team took the task of solving this issue that is naturally a global concern. They have developed a new type of concrete that can help reduce emissions produced by the construction industry. The novel calcium carbonate concrete proposed comprises waste concrete and carbon dioxide obtained from the air or industrial exhaust gas. The research has great potential as a future construction material and could increase demand within the Concrete Industry, especially for a location with a shortage of natural resources.
The team has successfully achieved a considerable feat by using waste concrete and capturing carbon dioxide for making concrete referred to as calcium carbonate concrete.
Researchers revealed that they were inspired by aquatic animals and their ability to harden into fossils in due time. They investigated if the exact mechanism that was used to create hard calcium carbonate deposits from dead organic materials could also be utilised to manufacture concrete. Calcium is known to be vital for causing a reaction between water and cement to form concrete. Thus, the team saw it as an opportunity to look into a less-carbon-intensive way of performing the same task.
Their concept entailed obtaining calcium through discarded concrete which is already regarded as a waste. They then combined the commodity with carbon dioxide acquired from industrial exhaust or air. In this manner, they achieved a much lower temperature than when calcium was extracted by burning limestone.
Calcium carbonate is a highly stable material; thus, it can act as a durable construction material. Further, the capability of recycling large quantities of material and waste is an immense benefit in itself. However, for now, calcium carbonate concrete is not capable enough to replace traditional concrete. It is not as hard as standard concrete, but this would not be a problem for some construction projects, such as small residences. At the moment, only little blocks a few millimetres long have been manufactured.
For now, the team has only managed to produce few locks of the material, but they are optimistic that the concrete holds great promise for the future and, in coming decades, might become the mainstream concrete.