Crushing Concrete into Dust in Mid-air

I have finally found some information which helps to explain why the two large towers of the World trade center turned to dust in mid-air, forming the mushroomed shaped clouds, rather than breaking up when if hit the ground.

This may or may not fit into many of our readers "picture of reality", but I atleast welcome something more than the non-explainations I have heard so far.

In order to cause concrete and steel to turn to micron-sized dust particles at Ground Zero as presented by Dr. Thomas Cahill, UC Davis Delta Group, the speed of sound must be reached in those items. Dr. Cahill is one of the world’s premier atmospheric physicists.

www.veteranstoday.com...

The speed of sound for concrete is 3200-3600mps (meters per second) and for steel the speed of sound is 6100mps.[1] Based on statements by Dr. Stephen Jones he estimates the velocity for his aluminum and iron oxide energetic compound in a silica substrate at 300mps.
According to Lawrence Livermore Laboratories the maximum velocity for an energetic compound made of iron oxide and aluminum in a silica substrate is 895mps.

There is even a paragraph which will appeal to those who so stongly disagree with Dr. Steven Jones.

Nano thermite is an incendiary. Explosives are classified as having velocities exceeding 3000mps. The incendiary nanothermite allegedly found by Dr. Stephen Jones is incapable of turning any component of the steel structured Twin Towers or the cement to micron sized particles or what is commonly referred to in scientific circles as ‘very fine particles’, as we all saw on 911 and as Dr. Thomas Cahill outlines.

I hope those who respond will take the small amount of trouble to read this article before exposing themselves as too reactionary to be bothered.

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Originally posted by Consequence
Are you drunk?

concrete is actually quite fragile and crumbles if not used right. A collapsing building is such a case.

Could you discribe to me the formulation for the concrete which you have used in constructing floor slabs for highrise buildings?

Of those on which I poured concrete, we used a mix which was rated at 3000 lb/in. This is normally enough for high traffic areas and stands up well for most general uses.

I would just like to know if a lighter mix could be used.

I also welcome you rapid reply.

Originally posted by hdutton
Could you discribe to me the formulation for the concrete which you have used in constructing floor slabs for highrise buildings?

I don't construct floor slabs.

Of those on which I poured concrete, we used a mix which was rated at 3000 lb/in. This is normally enough for high traffic areas and stands up well for most general uses.

That sounds sturdy.

I would just like to know if a lighter mix could be used.

The floors were light-weight slabs at least, for obvious reasons.
The exact mixture I don't know, nor do I care.

Again, what I wanted to say is that when concrete cracks, it crumbles, and things get quite dusty.
It is a clever way of spreading "truth" with "how fast does a slab of concrete need to fly to get dustified by air resistance". But that question is the wrong question to ask.

This doesn't even make sense. We can physically see that they are not reaching the speed of sound, and that wouldn't make steel disintegrate anyway! In order to disintegrate matter, you'd need a massive source of energy. Since the ground crews were able to recover just about all the steel, I'd have to argue that the steel did not disintegrate. And you are talking about disintegration, not dustification. I refuse to use a made-up term just because it makes your story more believable without evidence.

reply to post by Consequence

Again, what I wanted to say is that when concrete cracks, it crumbles, and things get quite dusty. It is a clever way of spreading "truth" with "how fast does a slab of concrete need to fly to get dustified by air resistance". But that question is the wrong question to ask.

The best way to answer this question may be to imagine concrete as a man made rock, which it is.

How far would a rock fall through the air before it is "dustfied by air resistance"?

Well, the answer to this is ... some where close to forever.

I have never seen it happen and I don't think anyone else has.

Originally posted by hdutton
reply to post by Consequence

 

Again, what I wanted to say is that when concrete cracks, it crumbles, and things get quite dusty. It is a clever way of spreading "truth" with "how fast does a slab of concrete need to fly to get dustified by air resistance". But that question is the wrong question to ask.

The best way to answer this question may be to imagine concrete as a man made rock, which it is.

How far would a rock fall through the air before it is "dustfied by air resistance"?

Well, the answer to this is ... some where close to forever.

I have never seen it happen and I don't think anyone else has.

Er.. yes, that is correct?
I believe you did not understand what I said.

Originally posted by Varemia
This doesn't even make sense. We can physically see that they are not reaching the speed of sound, and that wouldn't make steel disintegrate anyway! In order to disintegrate matter, you'd need a massive source of energy. Since the ground crews were able to recover just about all the steel, I'd have to argue that the steel did not disintegrate. And you are talking about disintegration, not dustification. I refuse to use a made-up term just because it makes your story more believable without evidence.

I was also glad to read your reply.

Might I point out that the term "dustify" was not mine, but atleast you took the time to read one reply.

From what I have seen in the past, that would indicate improvement.

reply to post by Consequence


My apoligies for misreading your statement about how fast rather than how far concrete would have to move through the air .

The article which I sited is not talking about the speed or velocity of the building material it's self but the speed of the shock wave moving through the material which distroys it. If you had read it you would have known that much .

reply to post by hdutton


Are you forgetting that a lot of the dust was the sheetrock and drywall that was crushed, aong with some of the concrete? Also, some concrete slabs will turn into powder form when it is cracked, smashed, or crushed. It is not a mystery. It doesnt even shock or surprise me.

reply to post by GenRadek


Sheetrock, gypsum, dust is white and very light in weight.

The dust which I saw, and the article speaks of, is the heavy dark gray cloud which falls and grows as the towers come down.

I hate to keep saying the same things over and over, but reading the article will answer many more questions about what we should be discussing.

Originally posted by hdutton
reply to post by GenRadek

 

Sheetrock, gypsum, dust is white and very light in weight.

The dust which I saw, and the article speaks of, is the heavy dark gray cloud which falls and grows as the towers come down.

I hate to keep saying the same things over and over, but reading the article will answer many more questions about what we should be discussing.

But So what was everyone covered in afterward? Drywall and sheetrock is not pure white snow. Also how can you tell the cloud is heavy? They found concrete compressed in the footprints of the WTCs and were cutting through them. Many of the floors were compressed together, concrete and trusses together. So that means a bulk of the concrete remained in the footprint AND was not dustified entirely. Each floor had TONS of drywall, sheetrock, and fireproofing, which was all getting mixed together and crushed.

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OP --

Maybe I'm confused about the point you are trying to make, but are you asking why there would be concrete dust from slabs of concrete that were blown apart by the impact of a plane and/or broke apart and fell hundreds of feet when the buildings collapsed?

Is that what you are asking?



Plus, just as another poster indicated above, can you please clarify the part about "the speed of sound through concrete and steel" has to do with those materials turning to dust? As far as I know, sound travels through those materials all the time at those speeds, without causing "dustification". Those speeds are simply the time it takes for a sound wave to propagate through those materials (sound travel faster through denser materials than it does through air).

I mean, if I knock on a piece of concrete with my knuckles, the sound of my knocking will travel through the concrete at 3200 to 3600 meters/sec, but that would obviously not cause the concrete to turn to dust....

...So what exactly do you mean when you talk about these speeds and dustification?

reply to post by Soylent Green Is People


As noted in the article; the speed of the pressure, shock, wave passing through a solid material must reach a certain velocity in order to break it apart. After this is accomplished the material will become as a podwer because the physical bonds are weakened to this point.

This pressure wave velocity is different for various materials but this shows the best senarios for what happened to the towers on 9/11.

There are very few ways such pressure wave velocitie can be produced, and thermite is not active enough to do so.

Originally posted by hdutton
reply to post by Soylent Green Is People

 

As noted in the article; the speed of the pressure, shock, wave passing through a solid material must reach a certain velocity in order to break it apart. After this is accomplished the material will become as a podwer because the physical bonds are weakened to this point.

This pressure wave velocity is different for various materials but this shows the best senarios for what happened to the towers on 9/11.

There are very few ways such pressure wave velocitie can be produced, and thermite is not active enough to do so.

While I agree with you in principle, I don't quite get what the speed of sound through the material has to do with the material turning to dust.

Like I said, if I simply knocked on a concrete slab with my bare knuckles, the pressure wave (the sound wave) created by my knocking would reach velocities of 3200 to 3600 meters per second -- because THAT is the velocity that sound (ALL sound) would travel through concrete.

I mean, it is pretty easy to get a wave to reach that velocity in concrete (just knock on it) -- so I don't think it is the VELOCITY that would cause the disintegration, but rather something else, such as the ENERGY in the wave. The energy of a wave is carried by the amplitude of the wave, NOT the velocity of the wave.

For example, my knocking on the concrete would create a wave of low amplitude, but smacking the concrete with a sledgehammer would cause a wave of higher amplitude. However, the waves from my knocking knuckles and the sledgehammer would both propagate through the concrete at the same velocity (3200 to 3600 meters per second -- just as would EVERY sound.

Can you please clarify what the author of the article means when he is talking about these velocities relative to the "dustification"? Again, I agree with you in principle, but I don't get the whole wave velocity thing.

Originally posted by hdutton
I have finally found some information which helps to explain why the two large towers of the World trade center turned to dust in mid-air, forming the mushroomed shaped clouds, rather than breaking up when if hit the ground.

To put it mildly, the collapses do not resemble the mushroom clouds of a nuclear explosion in the least. I see no reason to ascribe these collapses to nuclear bombs. And, I might add, mushroom clouds are not unique to nuclear bombs. any large enough explosion will cause one ,but that's not relevant, because there was no mushroom cloud on 9/11.

The OP linked article concludes that the demolition was accomplished by miniature nuclear weapons.

I think the analysis is nuts, and argues from a lot of false premises.

I don't know whether this 'speed of sound' dustification theory has any truth to it at all, but I dont think it's relevant for two reasons.

1. You don't have to accelerate anything to the speed of sound to get some dust out of it... You can create concrete dust with a hammer and your nearest sidewalk (and some elbow grease)

2. We know that the vast majority of the twin towers were NOT converted to dust.


The linked article makes some other errors and omissions that do not fit the facts as we know them.

3. If the twin towers destruction was accomplished by a nuke, how is it that the spire remained standing momentarily after the building collapsed?

4 The article states that "Nuclear devices as described herein were the only possible way to destroy the buildings without having enormous chunks of building debris fly all over NYC and smash down on dozens of surrounding buildings." That's a funny thing to say, seing as quite a few buildings were indeed hit by enormous chunks of debris. Using nuclear devices as a means of limiting collateral damage is counter-intuitive, to say the least.

I'm not buying the conclusions or analysis of this article.

reply to post by hdutton


Oh, you're talking about frequency of vibration, not sound velocity. My problem with this theory (if I'm understanding it correctly) is that a frequency that high would be audible, wouldn't it? It would also destroy everything, not just concrete.

Originally posted by Consequence

Originally posted by hdutton
reply to post by Consequence

 

Again, what I wanted to say is that when concrete cracks, it crumbles, and things get quite dusty. It is a clever way of spreading "truth" with "how fast does a slab of concrete need to fly to get dustified by air resistance". But that question is the wrong question to ask.

The best way to answer this question may be to imagine concrete as a man made rock, which it is.

How far would a rock fall through the air before it is "dustfied by air resistance"?

Well, the answer to this is ... some where close to forever.

I have never seen it happen and I don't think anyone else has.

Er.. yes, that is correct?
I believe you did not understand what I said.

I've never seen a scenario where the concrete just turns to dust. Can you show us some scenario that describes what you were refering to. I think that's what ^ concrete expert was trying to ask. I'd like to see anything similar.