How come I’ve done asphalt work 3 times already and can’t get past it?

You finish it completely. Then every time you enter afterwards, and do the same thing over, until the stage is completed once more, you earn $. I think $300.00 (from memory).

The Junk Yard is a similar thing (once you clear all stages), you are going in to collect the same thing, over and over, in order to be able to create certain items in the main area.