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- title: "annotation of the world's growing concrete coasts"
- layout: post
- category: responses
- tags: annotation
- replyto: "https://www.bbc.com/future/article/20200811-the-eco-friendly-alternatives-to-ocean-concrete"
- date: "2021-07-05T18:14:03.040748+00:00"
- hypothesislink: "https://hyp.is/xznHCt28EeupD8t2ZPKFUA/www.bbc.com/future/article/20200811-the-eco-friendly-alternatives-to-ocean-concrete"
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- > ...y useful for coastal hardening. <em>Bio-cement is formed by taking sand, or other forms of aggregate, and then adding bacteria and urea, a component of urine. The urea triggers the bacteria to secrete calcite – a form of calcium carbonate – binding the mixture together into a solid material similar to limestone.</em>
- “Bio-cement is certainly a more...
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- So biocement creates the calcite as part of production...
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- > ...cement, is another alternative: <em>bio-concrete. This is where bacteria called Bacillus pasteurii is actually encapsulated and added to the concrete, along with a form of starch that serves as its food. The bacteria stay dormant in the concrete until a crack forms and air gets in. This change wakes the bacteria up, and they begin to eat, grow and reproduce. In doing so, they excrete calcite, which bonds to the concrete, fills the crack and seals it up. So in essence, this type of concrete structure is capable of self-repair.</em> Natural habitats such as saltmar...
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- ....whereas bioconcrete leaves that potential dormant. (how long can that bacteria live like that?)
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