When you were a kid you were probably told to eat your vegetables if you wanted to grow up big and strong. Popeye the Sailor would also remind you to eat spinach if you wanted to pack a punch. Few engineers at the time, however, could have imagined that one of the key construction materials −concrete− would also benefit from the addition of vegetable components, carrots and beets specifically. But that is the central idea of an engineering department at the University of Lancaster (UK).
Currently, reinforced concrete can last for almost a century before maintenance costs shoot through the roof due to corrosion and cracks in the material, as well as the deterioration of the embedded beams. Hence, many scientists are researching new technologies to improve its durability. Some of the latest research carried out by the University of Exeter (UK) has suggested using graphene nanoplatelets to bolster the concrete structures. Having said so, producing graphene on an industrial scale is still a comparatively expensive and complex process. Why not look for other cheaper and readily available ingredients to improve upon the recipe and develop the building material of the future? Professor Mohamed Saafi, who has headed the project, wondered if using nanoplatelets synthesized from carrot and beetroot waste produced by the food industry could be a viable option.
Now, by adding those nanoplatelets to the cement mixture he has proved that they can become a source of calcium silicate hydrate, one of the hydrating products used in the production of Portland cement and the secret behind concrete’s hardness.
Professor Saafi and his team have shown that adding his nanoplatelets to the mixture allows saving forty kilos of Portland cement per cubic meter of concrete. The microstructure of the resulting material also has a higher level of density, which provides better resistance to corrosion too.
The cement industry is one of the most polluting and water-hungry, so reducing the amount of cement needed for the mixture and improving the durability of the concrete is indeed an eco-friendly solution.
Finally, the team is also studying the possibility of synthesizing a nanoplatelet film than can be applied to existing concrete structures, so they can benefit from its properties.
Duct tape from trees
Carrots and beetroots are not the only raw materials from the vegetal realm that are being used to improve industrial processes. Lignin is a natural polymer found in trees that is usually discarded during paper production. However, at the University of Delaware (USA) they have other plans for this substance, as they have just filed a patent for a system that decomposes lignin molecules into smaller ones with sticky properties.
Their tests show that it is possible to create a recyclable and eco-friendly duct tape as efficient as any of the conventional products already available in the market. This material would also allow creating bandages and plasters. The varying levels of stickiness can be achieved because each tree species boasts different properties. In fact, in a distant future, even tires could be made from lignin.