Concrete is an excellent and versatile material, but it is not without its limits. One of the biggest problems that equipment scientists are eager to find a bypass is its fragility. Concrete does not at all have a very high resistance to tensile, which means that it is subject to cracking under stress.
One way to solve this problem would be to develop concrete that can fill your own cracks, and a new method could be this panacea. A team led by the engineer in Congrui Mechanics Grace Jin from the Texas A&M University developed concrete which can be healed by exploiting the power of the synthetic lichen.
He improves on previous attempts To create self-healing “living” concrete made using bacteria, researchers say, being fully autonomous.
“The self-healing concrete mediated by microbe has been widely studied for more than three decades”, ” Jin explains“But it always suffers from a significant limitation – none of the current self -healing approaches is entirely autonomous because they require an external supply of nutrients so that healing agents produce repair materials continuously.”
Approaches using bacteria, for example, can force humans to spray nutrients by hand to encourage organisms to go to work to repair damaged concrete. In an article written for the first time by Nisha Rokaya of the University of Nebraska-Lincoln, Jin and his colleagues adopt this approach a little further.
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Lichens are not unique organizations, but examples of compulsory mutualism, a symbiotic partnership between the fungus and cyanobacteria or algae. The researchers have designed a tailor -made lichen using cyanobacteria that fix carbon dioxide and atmosphere nitrogen, and a filamentous fungus that attracts ionized calcium and promotes the precipitation of large amounts of calcium carbonate – the material that makes shells, sea shells, corals and chale.
In laboratory tests, these lichens were able to cure cracks in concrete by depositing large amounts of calcium carbonate, sticking the crack together and preventing it from spreading further. It is actually not different from Ancient Roman self-healing concrete which uses chemical reactions to produce calcium carbonate to repair concrete.
Unlike bacteria approaches, the lichen does not need to be nourished: it drags, doing its thing and does not need to be treated by humans. It must also be studied – the researchers follow the following plan to see how the lichen deals with pre -existing cracks – but it could present a means of improving the life of a material which has become essential to the lifestyle of humanity.
“The results have shown the potential to create a stable photo-heterotrophic system for repairing self-entrepreneurial concrete”. Researchers write“Use the capacities of two species simultaneously and eliminate the need for exogenous nutrient supplies”.
The results were published in Materials today communications.