Cement, gentlemen: it is by far the most popular building material on the planet. Strong, easy to work with and quite inexpensive. Clearly not without problems (duration first of all), but a team of Dutch scientists has developed a biological additive capable of making this material an even more resistant and self-repairing biocement.
There is a whole class of bacteria that can restore cracks and flaking in concrete, in a similar way to that developed by humans to heal a wound.
The procedure - Nutrients and a mixture of tiny ceramic spheres containing bacterial spores are mixed with the cement, which remain inactive until they come into contact with water: when the cement cracks and absorbs moisture, the spores 'activate' transforming the calcium present in the nutrients in limestone, which fills the cracks.
Bacteria are unable to repair large cracks in concrete: at present their capacity stops at 'gashes' (I laugh) of just half a millimeter. Then I think about it and stop laughing: the vast majority of concrete problems are caused by small cracks (sometimes even invisible to the naked eye) that worsen with water and humidity and undermine the solidity of the whole, pulling a structure down when they start to add up. Biocement solves a lot of problems.
Costs - Adding nutrients and bacteria to cement is not free: costs would increase by about 50%, but beware: currently, in a construction, the cost of cement is around 1-2% of the total, so the overall cost would really increase. a little. Rather, keeping a building tidy while preventing it from collapsing can be MUCH more expensive.
When will bio cement be available?
- The 'biocement' is being tested in outdoor environments and will be commercialized within two years. Then it will also be up to the bioceramic.
If you want to know more, here is the reference of one of the Dutch researchers who is dealing with the project:
Henk Jonkers, Faculty of Civil Engineering, Geosciences and Sustainable Building.
E-mail: [email protected]
website: www.dcmat.tudelft.nl
