21st May 2021
The world’s first graphene concrete slab has been laid commercially, a milestone that helps significantly reduce the environmental cost of concrete.
The new hybrid material is 30 per cent stronger than standard concrete, which significantly reduces the amount required for building projects and surfacing contractors.
This breakthrough was the result of a joint project between the University of Manchester and Nationwide Engineering, who laid the slab down at the Southern Quarter Gym in Solstice Park in Amesbury, a few miles east of Stonehenge.
The single floor slab was made by what the team have called concretene, which removed much of the building material and all of the steel rebar that is standard with concrete construction projects.
A representative of the University of Manchester called the project a breakthrough that could revolutionise the concrete industry and reduce its significant effect on the environment.
According to their data, if concretene is used worldwide, it could on its own reduce carbon emissions globally by 2 per cent, a reduction equal to the entirety of the shipping industry.
Why Is Concrete An Environmental Issue
The production of concrete is the third-largest emitter of carbon dioxide emissions, behind only the overall emissions generated by China and the United States of America.
Part of this is a result of the chemical process used to make cement, which releases carbon dioxide and lime when calcium carbonate is heated. The other part is the energy required to heat the cement to form clinker, often to temperatures above 1500 degrees Celcius.
As well as this, concrete production requires a lot of water, currently amounting to 1.7 per cent of all water use.
Finally, most construction concrete is reinforced with steel rebar, which gives concrete tensile strength and reduces the risk of cracking. However, the steel required has its own carbon cost as well.
There have been other suggestions to reduce the effect of concrete on the environment, such as using fly ash, slag or bottom ash to replace clinker, as well as mixtures that can bond more effectively with less water.
The simplest way to reduce the impact concrete has on the environment is to require less of it. This would require less heat to create it, less carbon dioxide emitted during the process and less water needed to start the mixing process. This is where concretene comes in.
How Does Concretene Work?
Concrete sets through two chemical reactions known as hydration and gelation. Hydration is where the cement reacts to the water and gelation is where this paste mixture bonds and hardens. Once dry it becomes an exceptionally strong material.
Adding graphene helps in several ways. The first is that it acts as a mechanical support that increases the strength of the concrete. As well as this, it also serves as a catalyst surface, which makes the bonding process more effective.
The result is concrete that is stronger, more durable and more resistant to corrosion.
Whilst the process of creating concretene is different, the process of mixing it, laying it and letting it set has not changed, meaning that no extra training or equipment is needed on the part of the construction firm.