BS. Heat up concrete to cherry red and the steel inside loses all of its strength. Might as well be pasta.
Whilst living in Houston a tanker carrying ammonia blew up in an underpass. Blew the concrete right off the rebar. Like a human skeleton. Took weeks to replace since all of the work had to take place around the other 6+ lanes in the same area.
I am very familiar with hot iron and steel.
I make stuff out of both all the time.