Does Concrete Turn to Dust in a Vacuum Chamber? Concrete Without Oxygen Experiment

By that logic, removing all oxygen would also turn the oceans into hydrogen gas.

dust is just boneless concrete

Concrete also typically has gravel mixed in too. Concrete after it hardens [it doesn't just "dry"] it is basically a rock. Rock don't require oxygen to maintain their cohesive density. If you put wet concrete in a vacuum it will dry/harden just fine. The quality of the concrete might be reduced because of the accelerated moisture removal via the vacuum.

As a masonry contractor, I'm quite familiar with the properties of concrete. Concrete will even set up even under water. The reason the concrete set up slightly slower in the vacuum isn't because of lack of air but rather lack of air movement. Mortar on a corner of a building will set up faster than the rest of the wall because it experiences more air movement like wind reducing the moisture content. While this does make it set up slightly faster it does not strengthen the concrete in the long run. In fact wetting the concrete and keeping it wet during the first 7 days of the concrete cure will increase the cure time slightly but can greatly increase the strength of the concrete when fully cured, as well as more evenly cure preventing cracks.

I feel like "if all oxygen disappeared concrete would crumble" is based on some ridiculous, hypothetical case of "aliens literally took every oxygen atom off the planet", at which point crumbling concrete would be the least of our concerns.

She: Honey, what are you watching? Me: What happens to concrete in a vacuum. She: Alright, what does happen to concrete in a vacuum? Me: Well, nothing. ...

I love how Action Lab knows the result, but he takes his time to do all these experiments anyways to settle these myths once and for all.

Very patient, good job. I sure hope most schools are still teaching very basic chemistry, but starting to have my doubts....

There’s rocks in space, so I’d assume it’s still solid in a vacuum.

people: "all the concrete would turn to dust if we removed the oxygen!" the concrete without oxygen:🗿

Really interesting. I'm not a chemist so it was really nice to have the chemistry explained!

I just watched this one, I love your vacuum chamber did you build it or buy it? The landscape stone you used may not be just concerned. The company I worked for, which I'm not moving right now, would donate their solid waste from paint and polymers to mix into concrete for landscaping stones. This was an environmentally safe way of disposing of solid paint waste. As well as it added strength to the landscaping stones and they could use it for coloring I believe as well it was told to me. I don't know if having a polymer in the Stone as a binding agent to the concrete would add anything else to it. I was also wondering if it had any air pockets in it that would pull the air out during the vacuum. I'd be interested to see what that vacuum chamber would do to certain natural stones or geodes since they usually carry some level of moisture or air pockets in natural stones.

Concrete: does not turn to dust Thanos didn't like that

you can’t pull out oxygen that’s already bonded to the concrete molecule

I may be mistaken, but concrete is a product of hydration, where the water allows the cement particles to come together around a molecule of water. Considering that there is hydraulic cement, which doesn't need oxygen to make. The hydrating water is essentially locked in a crystal cage. The only thing that a vacuum might do is lower the vapor pressure which allows the water to escape the cement. Probably not enough to free the bound water, but it might require less energy when you apply heat to it. If you apply enough heat, the water breaks out of the concrete, and you're back to the initial ingredients. Limestone is an example of a rock which needs water to be in rock form. If you heat it, it turns into burnt lime (Calcium Oxide). I think there are some products which might be weak enough where a vacuum might liberate the water molecules.. maybe gypsum or epsom salts. Vacuum distillation and vacuum drying is a think (freeze drying is forcing the water to crystallize and sublime out). Interesting question, but boring answer ;)

Appreciate everything you fill my brain with but also, awesome shirt!

They mean that it would collapse if every oxygen molecule inside the concrete were suddenly removed, which is impossible to test

1:00 clarifies the difference between concrete and cement 5:34

That was really interesting. I heard that the ancient Romans knew how to make concrete that could set underwater. I'd love to see you do something with that. Maybe an explanation of the differences between it and normal concrete or some kind of side by side experiment.

I'm glad you made this.