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

Apr 01, 2022
Okay everybody, today we're going to see what happens if you put

concrete

in a

vacuum

chamber

, so the reason I'm doing this video is because I've gotten a lot of requests to do it. There are apparently several videos circulating online. with the question what would happen to the earth if the

oxygen

disappeared for five seconds and in all these videos they always mentioned that if the

oxygen

disappeared from the earth for five seconds, all

concrete

structures would just fall to the ground because they depend on oxygen to stay rigid so a lot of people have asked me if that means if we put concrete in a

vacuum

chamber

it will

turn

to

dust

ok today we're going to find out so I'm going to put concrete in the vacuum chamber and see what happens to it and then , after that test I'll do one more test in the vacuum chamber and see if it really needs air for the concrete to solidify, so what happens if we have wet concrete and we try to leave it? dry in the vacuum chamber is dry or not ok so i have a brick of concrete here so before i put this concrete let's clarify the difference between concrete and cement so you use cement to make concrete basically you mix cement with sand and that makes concrete so usually when we're just talking about we interchange concrete and cement but they're really different things so I'm using concrete which is a mix of cement and sand or some other aggregate okay, now it's time to guess what you think is going to happen is this concrete block just gonna

turn

to

dust

or just stay as it is or what's going to happen here so i want you guys to comment in the comment section with what you think it's going to happen and how sure are you that it's going to happen i know i've got my guess right solid concrete in a vacuum chamber will crumble to dust three two one we're dropping pressure fast we're in n half an atmosphere now a third of an atmosphere what it looks like

does

n't look like much is happening let's get to full vacuum and see what's happening here ok we're almost full vacuum now let's give it a few more minutes cracks are forming let's see ok now we're in a full vacuum as much as my vacuum the pump can pull now and it looks pretty solid to me it definitely didn't turn to dust ok let's let the air back in and check it looks as strong as it may be the solid concrete still has no dust at all, in fact it has no effect on the concrete OK, now let's see what happens trying to dry the wet concrete in the vacuum chamber.
does concrete turn to dust in a vacuum chamber concrete without oxygen experiment
Does concrete really need air to dry? Alright, here is our concrete mix mixed with a little bit of water. Okay, this is a quick-setting concrete. 40 minutes, one thing that I noticed right away is that this concrete is now warm, so none of the ingredients that I put into it were warm, which means that a chemical reaction is taking place and that chemical reaction is called hydration. I'm going to p We put one of these in the vacuum chamber and one of them outside the vacuum chamber and we'll leave them there to sit and then we'll check and compare their properties to see if one of them is harder than the other or one . of them stayed completely wet and never dried out let's see what happens ok wet concrete in the vacuum chamber three two one ok here we go to mid atmosphere so it

does

n't look like much is happening to the wet concrete in there .
does concrete turn to dust in a vacuum chamber concrete without oxygen experiment

More Interesting Facts About,

does concrete turn to dust in a vacuum chamber concrete without oxygen experiment...

I don't see anything boiling water or anything so I've got my two samples now so I'll let this one settle and I'll go back and compare to the one in the vacuum chamber so I can see that the cement really didn't do anything in the vacuum chamber empty, so why do all these videos mention that if we lost oxygen from the atmosphere, all these concrete structures would just collapse to the ground? Well those videos are actually a bit misleading because they are really mixing oxygen oxygen gas and the oxygen that are inside other molecules now obviously these two are extremely different and this is where the confusion arises with the concrete structures being they crumble if oxygen is removed so the cement that holds concrete together has many different components but the main component is called tricalcium silicate it's about 55 portland cement and this is what a molecule of tricalcium silicate looks like it's made of calcium silicon and oxygen atoms but because this is such a big name to write many concrete engineers actually use a shortened form of this they actually write it as c3s so if you're a chemist this it's a bit confusing because it looks like a weird molecule with three carbons and a sulfur atom, but it's really just an abbreviation for this tricalcium silicate .
does concrete turn to dust in a vacuum chamber concrete without oxygen experiment
Now this tricalcium silica reacts. with water and it's called hydration and the chemical reaction when it reacts with water is this so as soon as you add water to the cement it quickly reacts with t The water releases these calcium atoms and these hydroxide ions here so the ph quickly goes above 12 as soon as you add water to the cement and this reaction also produces heat so this calcium silicate and calcium hydroxide start to crystallize and harden so these crystals grow through the cement actually it makes it harder for the water to react with the tricalcium silicate and therefore slows down the reaction, so the initial reaction is really fast, but after a while it slows down considerably because this water can't get through very well, for example, you have your initial ball of cement here and the water surrounds it and the water reacts with it and forms this layer around it of this calcium hydroxide and calcium silicate and crystallizes around it. around and so it makes it harder for more water to get in, which is why the cement can take so long to cure because the water has to diffuse through this layer of glass here to get into the ball of cement. l inside of it so you can see that in this reaction here I didn't mention an oxygen gas molecule at all which means this reaction doesn't depend on air at all just water so technically those videos were correct because if you remove the oxygen atoms in all these molecules of course wouldn't stick together, in fact there would be a lot wrong if you suddenly took out all the oxygen atoms, but I think a lot of people got confused and assumed they were talking about oxygen atoms molecular like the gaseous oxygen we breathe they assumed that's what the video was talking about but actually they were talking about all oxygen atoms even within molecules ok so it's been a few hours so this is cement from fast setting so it should set pretty quickly it's definitely not full strength yet but it should be good enough to compare the two so let's compare our se filled with cement and air versus in a vacuum chamber let the air come back in three t Wow let's see how hard they are so let's try breaking one and vacuuming up a hat in half pretty easy at this point the one on air is also pretty easy now it looks like there isn't a huge difference here the color is slightly different this is a little bit lighter color than it was in the vacuum chamber so you can see that being in a vacuum vs being in the air didn't really change any of the curing properties of the cement here so it seems either we have an already dry concrete slab or whether or not we try to vacuum or air dry it doesn't really matter, it will dry out anyway either way or it will set either way whether or not there is oxygen or air around it okay so this is really good news this means we can use concrete structures in space the only thing about being in a vacuum chamber that could affect r cement is that it evaporates more water so technically if you have the exact right amount of water for cement and you put it in a vacuum chamber and try to let it react there.
does concrete turn to dust in a vacuum chamber concrete without oxygen experiment
Some of the water will evaporate before it has a chance to react, so you could end up with a more crumbly cement overall. Hey everyone, thanks for watching another episode of the action lab. I hope you liked it if you considered hitting that subscribe button and hitting the bell to be notified of my latest videos and if you have any comments or questions please let me know in the comment section and I will try to reach out to them and head over to actionlab.com for see the subscribe box if you haven't already and thanks for looking and see you next time

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