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It looked like regular concrete. It poured like normal concrete. But it had a superpower.
James Baker, CEO of Graphene@Manchester, couldn’t quite believe his eyes when he saw the installation of a new roller disco floor at Manchester’s Depot Mayfield development.
The concrete slab hardened so quickly and so strongly that the builders had started pushing polishing machines over the driest part of the floor while their colleagues were still pouring the other end of the track.
“Usually you have to wait a week before you can do that,” he says. The installation, last October, took less than a day.
This concrete was special because it contained a small but transformative amount of graphene, microscopic flakes of carbon atoms arranged in a honeycomb lattice.
Graphene is the strongest material ever discovered, but has struggled for nearly two decades to find a revolutionary role in commercial products. Is that about to change?
Besides improving the mechanical properties of certain materials, it is hoped that graphene can also make some projects more environmentally friendly.
“By adding as little as 0.1% graphene to cement and aggregates, you can potentially use less material to achieve the same performance,” explains Mr. Baker. Reducing the amount of concrete used in construction, for example by 30%, could reduce global CO2 emissions by 2-3%, he estimates.
As well as the roller disco, Mr Baker and his colleagues have also tried the graphene-infused concrete, known as concrete, in a gym floor in Wiltshire and some road projects, including a section of the A1 several hundred meters long in Northumberland.
The team will also pour concrete in an as-yet-undisclosed project in the United Arab Emirates this year.
These early attempts have involved fairly simple projects, Baker explains — floor slabs, rather than walls or elevated platforms, which can be more risky. So far, however, the concrete has performed as expected.
But why does graphene have this effect on concrete? Carbon fibers have previously been used to reinforce concrete and graphene (although flakes of it are much smaller in size than carbon fibers) play a similar role, says Lisa Scullion of the University of Manchester’s Graphene Engineering Innovation Centre.
However, there is more to it than what happens. The fragments of the graphene can also change how the concrete settles around it.
“It almost provides nucleation sites on the surface of the graphene, to regulate that structure in the concrete,” says Dr Scullion, adding that researchers are still working out the implications of this. It can make the concrete denser, or change the structure of the pores in the concrete.
Maybe something closer to a block of cheddar, as opposed to Swiss cheese, I suggest.
That is enough to remove the requirement for reinforcing steel in the concrete in some applications, says Dr Scullion.
In addition to concrete, graphene can also improve the durability of paint and coatings, and prevent rust. “Because you have all these little tiny flakes, water and corrosive ions can’t penetrate to the metal as quickly,” says Dr Scullion.
And by improving the strength of building materials, architects could one day design much more elaborate and irregular facades, perhaps some inspired by forms in nature, suggests Pasquale Cavaliere of the University of Salento.
Graphene has been the subject of excitement for years, ever since it was discovered at the University of Manchester in 2004. The hype surrounding it has itself become the subject of study, and there are some who remain skeptical that it will live up to these lofty the expectations.
The buzz around graphene has led to a “wild west” situation where some products containing the material may be highly priced, but actually low quality, said Krister Svensson, associate professor of physics at Karlstad University in an interview published in 2019.
He tells BBC News that the quality of the graphene used today varies greatly. In addition, he questions whether the use of graphene as a reinforcing agent is really necessary, since graphite and carbon fibers can play a similar role.
“Graphene is still relatively young,” admits Mr. Baker. But he and his colleagues are determined to “accelerate the adoption of graphene,” he adds.
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Companies that have experimented with the material have sometimes found that it has slightly different uses than what they originally intended.
“We love graphene,” says Debbie Mielewski, technical fellow for sustainability at Ford. She says that since 2018, the automaker has shipped between six and seven million vehicles, mostly in North America, that contain graphene in a handful of parts.
Initially, she and her team were interested in graphene for its strength-enhancing abilities. But they found that it was actually more useful in terms of reducing noise and vibration, or improving heat resistance.
Cars including the F-150 and Explorer SUVs now contain 12 small components in and around the engine such as pump covers or water pipe supports that feature graphene, in part because it absorbs noise.
Depending on the frequency of the sound in question, these components can reduce noise heard inside the vehicle by between 12% and 25%, says Dr. Mielewski.
It has also made these parts lighter, lowering the car’s overall mass by approximately 680g. This means that these vehicles use slightly less fuel and therefore have lower CO2 emissions over their lifetime.
Ford is working with US firms, XG Sciences and Eagle Industries, on various graphene applications.
Dr. Mielewski says that the automaker is investigating the possibility of adding graphene to plastics inside the vehicle to make them stronger, but explains that so far they have not been able to disperse the graphene in the plastic as well as hoped.
This is often an important stumbling block when adding graphene to a particular material. To actually improve the properties, the graphene must be distributed evenly. However, depending on how the material is formed or mixed, and the temperatures and pressures involved in that process, it can be difficult to achieve the desired result.
It’s a bit more complicated than this, but imagine trying to get an even spread of raisins in a fruit cake when the batter is too runny.
Getting a wonderfully even mixture, and a material that is unequivocally improved by the addition of graphene, is what all these researchers and companies are aiming for.
Because with graphene, the proof is definitely in the pudding.
