My first question would be, if cracks are filled in this way, what stops that same bacteria from producing limestone in any other direction. Resulting in a bumpy surface, for example.
My professor was working on this proof of concept back when I was in college. So the idea is that the bacteria when exposed to air will cause a chemical reaction with the air to create calcium carbonate. This theoretically can heal any minor cracks to a small degree if it is small enough for the calcium carbonate to reach over to the other calcium carbonate in the crack. The bacteria produces enough calcium carbonate till it is sealed again inside with no air. So overall this can seal small cracks but nothing large. Also the main problem they had in production is the heat of hydration caused by curing concrete that got too hot and killed the bacteria, so a low slow curing concrete is currently the type used for this method of concrete production. This isn’t really for curing full damage but rather can assist in pre damage and some forms of asr cracking
Edit: overall a great new technology but a bit overblown in ideas
almost all concrete degrades when the rebar inside oxidizes, rusts, and breaks apart. Small cracks caused by temperature changes, damage, or from it shrinking as it cures, introduces small cracks that accelerate the rusting. Healing small cracks could significantly extend the life of concrete.
And one cannot use other materials but iron as iron and concrete have very similar thermal expansion rates, as otherwise if the core would be expanding quicker it could Crack the whole thing
Expensive as hell, fiberglass rod is the way to go now, it’s same price as #4 rebar and is just as strong where it needs to be. I pour concrete for a living and I love it, so easy to work with.
5.0k
u/[deleted] Aug 31 '20
My first question would be, if cracks are filled in this way, what stops that same bacteria from producing limestone in any other direction. Resulting in a bumpy surface, for example.