Three comments:
Our driveway is about 400 feet long. We took out 6" of dirt by using a tiller and scoop. Then laid down the matt and put in gravel.
We thought putting own the recycled asphalt would be just the ticket, but when we put down four loads of recycled asphalt two years ago, it became a total mess! Turns out that around here any recycled asphalt is used on the roads if it is clean. This had all sorts of dirt in it. Every time it rained or during the winter when the driveway was wet, we had the mud all over. Last spring we put two loads of crushed rock on top of it and have had not problems.
Someone mentioned that some states have machines that recycle road material. Our oldest son was in college with one of the Mannat boys. They are the firm in Iowa that has done all the research and development in recycling roadways. Turns out they save lots of money for the taxpayer and do the job in MUCH less time.
If you would like to check them out here is a link
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