Carrots n' beets used to strengthen concrete
It was just back in April that we heard about how scientists had made concrete stronger and more eco-friendly by adding graphene to it. Now, researchers at Britain's Lancaster University are reporting that they've achieved even better results using less-expensive "nano platelets" derived from root vegetable fibers.
The proof-of-concept study is being led by Prof. Mohamed Saafi. He tells us that the cellulose-based platelets (which were produced in collaboration with Scottish firm CelluComp) are basically "nano sheets synthesized from carrot and sugar beet root." Those vegetables were obtained as waste products from the food industry.
When added to a traditional concrete mix (cement, aggregate and water), the platelets increase the amount of calcium silicate hydrate – it's the main product of the hydration of widely-used Portland cement, and is chiefly responsible for the strength of concrete.
In lab tests, adding the platelets made concrete significantly stronger, to the point that 40 kg (88 lb) less Portland cement per cubic meter of concrete was required in order to achieve the same strength as would otherwise have been possible. This means that less concrete would need to be used in any given structure, which is important to the environment, as cement production is a large source of manmade carbon dioxide emissions.
Additionally, adding the platelets was found to boost the density of the concrete's microstructure, which would allow structures to last longer by being more resistant to corrosion. As a result, those structures wouldn't need to be replaced as often, further reducing the amount of cement required by the construction industry.
"The composites are not only superior to current cement products in terms of mechanical and microstructure properties, but also use smaller amounts of cement," says Saafi. "This significantly reduces both the energy consumption and CO2 emissions associated with cement manufacturing."
The scientists are also looking into creating thin nano platelet-based sheets, which would be applied to the outside of existing structures made from traditional concrete. The sheets could increase the lifespan of those structures, by providing additional strength.
Source: Lancaster University