President Trump is claiming the strikes “obliterated” three underground nuclear sites in Iran protected by military grade concrete. The truth may be more complicated.

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.”

    • Saleh@feddit.orgEnglish
      2·
      5 hours ago

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

      • 3abas@lemm.eeEnglish
        2·
        4 hours 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.

      • unexposedhazard@discuss.tchncs.deEnglish
        212·
        17 hours ago

        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.

      • Fondots@lemmy.worldEnglish
        112·
        16 hours ago

        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.