Now we are talking some serious rebar!
They are making up mats that they will fly in place with a crane. The giveaway is the wooden 4x4.
I would say that is #6 bar or less as it is two guys handling it. When you get up to #8 and 9, then you are talking Steel.
I have had column or pier steel so dense you had to change the mix to pea gravel aggregate because normal 3/4 diameter aggregate would leave air pockets because the steel was so packed together.