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Very interesting! I was curious how this related to Roman self-healing concrete: https://news.mit.edu/2023/roman-concrete-durability-lime-cas... and it seems like this is an entirely novel method, where little capsules of bacteria break open when a crack appears and then "heal" the crack through growth until they consume their food stock.

Both the capsule (alginate-based) and bacteria are common and safe

It's the same idea, but instead of calcium carbonate leaking out of quicklime in Roman concrete, it's done by bacteria.

The questions are if the bacteria will survive 50-100 years or more in the real world, and if this can be done economically at scale. My guess is no, it's more of a science experiment or something to be used in niche applications.

https://www.sciencedirect.com/science/article/abs/pii/S09500...

They produce 60-80 milligram of calcium carbonate 'per fiber', per 30 hours. I'm interested to know how they keep the bacteria alive over time, through the concrete curing process (high temperatures, high level of carbon dioxide, making any liquids in the vicinity highly acidic), and how the bacteria remain viable over time. Concrete we consider to last over decades, or a century?

Relatively common for bacteria to turn itself into an spore form when it's unhappy with the environment. Can last that way for a very long time.

> high level of carbon dioxide, making any liquids in the vicinity highly acidic

Isn't concrete very alkaline by itself? Also where is the carbon dioxide coming from?

I'm curious why they are looking to make new concrete fixes. Would using microplastics and bacteria in the current existing concrete possibly help fix the current breakdowns of old crumbling concrete? It could be a quicker and less bloated fix to the current infrastructure issues.

> if we work out the kinks and manage to bring it to the market one day, could extend the life span of concrete.

If, could, one day; it sounds like one of many revolutionary battery technology releases, and definitely not the first self-healing concrete innovation either.

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And yet we do with concrete, as observed here.

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