Spent asphalt has been heavily recycled for many years in making new asphalt. It's excellent for reuse into new pavement duty.
Oil refinery trivia…. Asphalt oil is the heavy residual oil remaining after all the good stuff has been stripped and distilled from the crude oil. The only thing lousier than asphalt oil are the slop oils removed from water at the front end of the wastewater treatment plant. This slop oil is the feed to the Coker Unit, that uses steam and temperature to yield petroleum coke. The coke product has a high energy content and supplements coal as a fuel.
It was a combination of granulated rubber and regular road asphalt. Laying it down was a struggle, keeping it warm enough to spread and compact but not lighting off from the tiger torches was a real balancing act. Then after it was laid longevity became an issue.
A pretty good-seeming idea that failed.