this post was submitted on 25 Jun 2025
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273
In a First, America Dropped 30,000-Pound Bunker-Busters—But Iran’s Concrete May Be Unbreakable, Scientists Say (www.popularmechanics.com)
submitted 23 hours ago by [email protected] to c/[email protected]
98 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] 3 points 8 hours ago* (last edited 8 hours ago) (2 children)

How is the fleet holding up?

We almost made it this time!

Oh well, let's freeze another fleet, wait for January and try again

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

I think that was kinda the idea - war production meant steel was in great demand, and this seemed like a really cheap way to make ships. I wouldn't want to try sailing one round the Caribbean, but they might have been okay in the north sea, for example. They didn't work out though, can't recall why but it's not impossible that melting may have been a factor!

[–] [email protected] 1 points 2 hours ago

The idea was to build giant floating barges in the mid North Atlantic for sub hunting escort aircraft to refuel halfway across. The escort aircraft at the time couldn’t stay with the convoys the whole way, leaving a stretch in the mid Atlantic where they were vulnerable. An ice runway would allow aircraft to cover the convoy for the entire passage, and in the North Atlantic would last months (if not longer) before melting.

[–] [email protected] 3 points 6 hours ago

Look up pykrete, it’s actually a really cool material