Prison cells (whose rooms are cast concrete over rebar). AT machines. Vaults, safes... Lots of things. Roll-up shutter doors... fences around construction equipment.
Not enough people are tunnelling their way out of prisons to justify the expense of building prisons out of anything like this. And it's too bulky for shutters or fences.
Jail and prison are not the same thing. Jail is for light crimes - most people in jail leave every day to go to work, and then return to jail when work is over. It is easy to run, but odds are they will catch you (they know your family, job and friends...). It isn't uncommon for the windows to open without triggering even an alarm.
Prison is a level higher. You start out in a more secure setting where it is harder to do anything without getting caught. (if you only get 1cm of tunnel built it doesn't do you any good). If they suspect you are going to pull anything they move you to more secure prisons where you are watched closer.
You might be smart, but there have been lots of smart people in prison before you with nothing better to do than dream up every possible escape plan. They are gotten good at detecting and preventing them over the years. In short odds are against you getting out successfully, and the attempt will earn you more time in prison.
What construction equipment could possibly need an indestructible fence surrounding it?? Most construction sites have chain link or orange plastic fences, and they’re not to prevent theft. You hire security or insure the equipment against theft to protect against theft.
Anyone that owns heavy equipment carries insurance covering damage, theft, and liability. Otherwise it’s rented and Sunbelt or whoever is on the hook to replace it.
Safes and vaults might be a good application.