An interesting article from bbc explains how concrete treated with a species of bacillus can “heal concrete” cracks by making more limestone.
Experimental concrete that patches up cracks by itself is to undergo outdoor testing.
The concrete contains limestone-producing bacteria, which are activated by corrosive rainwater working its way into the structure.
The new material could potentially increase the service life of the concrete – with considerable cost savings as a result.
The work is taking place at Delft Technical University, the Netherlands.
It is the brainchild of microbiologist Henk Jonkers and concrete technologist Eric Schlangen.
If all goes well, Dr Jonkers says they could start the process of commercialising the system in 2-3 years.
From the article, it sounds like these are not engineered bacteria but engineering may increase yield.
“Micro-cracks” are an expected part of the hardening process and do not directly cause strength loss. Fractures with a width of about 0.2mm are allowed under norms used by the concrete industry.
But over time, water – along with aggressive chemicals in it – gets into these cracks and corrodes the concrete.
“For durability reasons – in order to improve the service life of the construction – it is important to get these micro-cracks healed,” Dr Jonkers told BBC News.
Bacterial spores and the nutrients they will need to feed on are added as granules into the concrete mix. But water is the missing ingredient required for the microbes to grow. Concrete is the world’s most popular building material, but cracking is a problem
So the spores remain dormant until rainwater works its way into the cracks and activates them. The harmless bacteria – belonging to the Bacillus genus – then feed on the nutrients to produce limestone.
The bacterial food incorporated into the healing agent is calcium lactate – a component of milk. The microbes used in the granules are able to tolerate the highly alkaline environment of the concrete.
The cost will be high per unit but in the overall scheme of things, reduction in maintenance and longer functional life will dwarf cost issues.
Tags: science
Interesting.
I often think that we are in a race between a growing dystopic society and technological progress. Much bad governance is covered by technological progress.
It is almost like we are creating a priest class: individuals sequestered from society by work/connections/ability that occasionally shower the masses with a new food/entertainment/psychopharmacological diversion.
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What are your thoughts on the election, Doc? The power of incumbency is awfully strong, e.g. Bush in “04.
Public life is almost exclusively a liberal thing now. Obama and Romney both campaigned on the theme of “what government can do for you”.