The Autobahn pavement structure is a lot thicker that what I have seen of US highways. But there's also other things that went on the Autobahn. Tanks. In some cases, attack jets during exercises (Jaguars and A-10 Warthogs), however I doubt that is going on now.
That's true, over twice as thick, and meant to last twice as long (40 vs. 20 years). But there's still construction going on constantly. In 15 years there I can't remember a time when there wasn't construction on the parts of the A5 or A6 that I drove.
They did used to have a lot of tanks on the Autobahn, as NATO troops, including us, would use it all the time.