My son put up a 60'x80' with a 16' center high bay trailer shed. His asphalt contractor has done this for over 40 years. He recommended parking all heavy trailers on wood boards at least 3' long under each tire so as not to create a permanent low spot.
My trailer and tractor sheds are just limestone crusher run. If I had a choice/money I would rather have a concrete floor. Makes for a smooth hard surface for small wheels like my creeper or a trailer tongue jack with a wheel or a floorjack or other things we want to move around on small wheels.