A DUAL-USE technology is one that has both civilian and military applications. Enriching uranium is a good example. A country may legitimately do so to fuel power stations. Or it may do so illegitimately to arm undeclared nuclear weapons. Few, however, would think of concrete as a dual-use technology. But it can be. And one country—as it happens, one that is very interested in enriching uranium—is also good at making what is known as “ultra-high performance concrete” (UHPC).
Iran is an earthquake zone, so its engineers have developed some of the toughest building materials in the world. Such materials could also be used to protect hidden nuclear installations from the artificial equivalent of small earthquakes, namely bunker-busting bombs.

The above quote is from this wonderful Economist article, read it, as always clear prose, useful info well presented and minimal spin (&despite what some say that’s about as good as it gets spin wise if you want to explain/make a point.). It’s actually of general interest if you are interested in Civil Engineering or modern buildings and structures.
The point is that the US and others have been working on bunker busting for decades. The Massive Ordinance Penetrator shown dropping from a B52 above and in more detail below are the king of the hill right now.

Their reason for existence right now is to hold Iran’s nuclear bunkers at risk. The MOP is supposed to penetrate up to 200 ft of concrete:

The problem is that the work of Iranian engineers on tough concrete could mop up the MOP. The Iranians have added metal nano fibers and particles as well as fairly ordinary metallic, plastic and ceramic, whiskers, flakes etc to the mix to toughen the concrete in various ways. This work is being done to save lives world wide, including the US since it’s focus is on Earthquake damage reduction. But this is a wonderful example of dual use since exactly the same technology could make future bunkers all but impregnable to conventional weapons, which big as it is the MOP still is.
Bottom line if the best of the best tech were used they might get 6 or more times the strength and testing has shown just doubling concrete strength reduces penetration by more than half!
This is not good news and probably explains this:
Congress ‘Urgently’ Approves $82 Million To Improve Its Biggest Bunker-Buster
Despite this:
The 30,000-lb Massive Ordnance Penetrator Bomb Works So Well It Earned A Rare Honor
It would seem we may soon get a chance to see if the Iranians were smart enough to use the super concrete vs if our super bunker busters can slam, blast, burrow their way in. There is also the question of corruption, in a vastly corrupt civil society using expensive concrete which probably looks like any other concrete is an invitation for shaving. Many is the time when a fortress has fallen because of under spec materials. Also you have the long term espionage and internal strife driven sabotage the story is that bunkers for Nazi super Vengeance weapons were sabotaged by the addition of small amounts of sugar to the mix drastically weakening it.
This would all be a wonderful background for a comedic farce, if so many people’s lives were not at risk.

Enough said….