I have used it on both and yes it will throw the gravel. The issue I had was that I have river rock lining part of my concrete driveway and the blower picked up one of these about the size of a softball. It threw it around inside for a bit but ended up breaking the scraper on the bottom. Everything else held up, just the scraper broke. This is most definitely operator error and I explained this to EGO when ordering a new scraper but they replaced it under warranty anyway. So yes, I would say you can use it but just be careful.