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Self Healing Concrete?
Recently fellow member @TBA sent me a link reminding me about some new ideas in concrete technology I first heard about a year or so ago. Cracking, as you may suppose, is one of the biggest threats to the integrity of concrete structures. Water crystals freezing and thawing in a confined space of a crack can cause significant damage. Water can also deteriorate steel reinforcement, weakening critical parts of bridges, dams, etc…. Water and other chemicals and gasses can also make their way into a structure through micro-cracking, which is inherently present in concrete. The goal of “self healing” concrete is to figure out an additive to the mix that will repair cracks as they occur. Researchers have discovered a few kinds of ureolytic bacteria that can be mixed in the concrete when it is produced and lies dormant in the hardened concrete. If it is ever exposed to water through a crack however it will activate and produce limestone to fill the crack automatically. Here is a short video explaining the basics:
This is still in the research phase but there seems to have been significant progress made in the year or so since I first heard about it and could have tremendous impact on infrastructure projects like bridges, walls, damn and really any exterior concrete exposed to the elements.
Published in General
This is actually a pretty big deal as it addresses one of the three guarantees of concrete as taught to me by my first and favorite concrete boss.
1. It will get hard.
2. It will crack.
3. No one will steal it.
I think you could add another one: There are no small errors in concrete.
Rules to live by right there
There is nary a crack to be found in the 1100 sq feet in our garage and garage office floors we had poured in 2006. About 1100 sq ft. I did all the prep work myself and wouldn’t think of letting anyone else do that part. Nobody could possibly make any money at it the way I went about it. But give it time, I suppose. It did get hard and nobody has stolen it, so I suppose there is one to go.
Does your garage floor have saw joints in it or another type of “control joints?
It’s actually the 24×24 garage plus two adjacent slabs at a slightly different level (due to not being able to convince the elderly inspector that I should be able to do it according to the new, soon-to-be adopted codes). No control joints in the garage, but there are control joints in the two other slabs. They are not sawn joints; I don’t know the right term for them.
There is pex tubing in all the slabs. The garage proper where cars are parked is a 5 inch slab, if I remember correctly.
@Concretevol doesn’t want to be taken for granite . . .
There are shrinkage reducing additives that you can put in concrete that control shrinkage, and hence, cracks.
Was asking because if there is a control joint in the slab, your crack is at the bottom of that joint. If there is no joints in a 24 x 24 you are also a little lucky as that is on the large side for a slab to not have any control joints using standard mix designs.