this post was submitted on 25 Jun 2025
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401
In a First, America Dropped 30,000-Pound Bunker-Busters—But Iran’s Concrete May Be Unbreakable, Scientists Say (www.popularmechanics.com)
submitted 6 days ago by [email protected] to c/[email protected]
113 comments fedilink hide all child comments
 

Previously, a yield strength of 5,000 pounds per square inch (psi) was enough for concrete to be rated as “high strength,” with the best going up to 10,000 psi. The new UHPC can withstand 40,000 psi or more.

The greater strength is achieved by turning concrete into a composite material with the addition of steel or other fibers. These fibers hold the concrete together and prevent cracks from spreading throughout it, negating the brittleness. “Instead of getting a few large cracks in a concrete panel, you get lots of smaller cracks,” says Barnett. “The fibers give it more fracture energy.”

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[–] [email protected] 24 points 5 days ago* (last edited 5 days ago) (2 children)

Basically they used pyramid age tech to outplay billions of dollars worth of weapons tech.

[–] [email protected] 12 points 5 days ago (3 children)

Hardly. Did you read the article?

[–] [email protected] 21 points 5 days ago (1 children)

The greater strength is achieved by turning concrete into a composite material with the addition of steel or other fibers.

Fiber reinforcment is thousands of years old.

[–] [email protected] 17 points 5 days ago (1 children)

Calling that pyramid age I think is a little disingenuous, they didn’t have 40,000 psi concrete back in those days.

[–] [email protected] 2 points 5 days ago

Thats fair yeah

[–] [email protected] 11 points 5 days ago* (last edited 5 days ago) (1 children)

So I did not read the article because of a paywall I'm too lazy to circumvent right now

But from OP's summary, the main technology they're talking about is concrete reinforced with steel or other fibers.

And that's definitely more advanced than "pyramid age"

But it's also pretty much a direct descendant of mud brick reinforced with straw which humanity has been using since well before the pyramids. Same basic concept, different materials.

So yes and no.

[–] [email protected] 6 points 5 days ago

Yes....no.....maybe? I don't know. Can you repeat the question?

[–] [email protected] 6 points 5 days ago (1 children)

Egyptians stacked blocks of stone to build the pyramids.

Roman concrete was impressively strong.

Neither of them had steel-reinforced concrete.

Neither did Gothic cathedrals, which is why they needed flying buttresses.

Reinforced concrete as we know it today is a 19th century innovation, as I understand it.

https://en.wikipedia.org/wiki/Reinforced_concrete?wprov=sfla1

Maybe the commenter was thinking of adobe.

[–] [email protected] 2 points 5 days ago

And this tech goes way beyond merely "reinforced".

[–] [email protected] 3 points 5 days ago (1 children)

Arguably letting a big weight fall down after being brought into the air somehow is also pyramid age tech.

[–] [email protected] 2 points 5 days ago

These bombs are not just dead weights. These bunker busters are equipped with precision guidance and fly to and hit a person on the head if they desired. It's also designed to deliver a huge explosion AFTER it penetrates with the kinetic impact.

It can also be set to explode right before impact, like Israel really likes to do when attaching residential high-rises, to deliver maximum destruction and death.