Concrete is a generally defined as any mineral aggregate (so rocks and stones) mixed with a binder (normally cement, but bitumen in the case of asphalt).
As for why roads are normally made out of “normal” concrete, it’s very expensive to build roads like that. Pavements are cheaper to build out of concrete because they only carry the weight of pedestrians, not lots of rolling vehicles. You need a pretty thick slab with rebar in it if you want to build a road surface from it, due to how weak cement concrete is under tension. Asphalt concrete cheats by being flexible, so minor imperfections in the surface or sub-base don’t become sources of critical failures (although they can become pot holes). Asphalt is also cheaper and easier to patch repair, but doesn’t last as long as proper cement road surfaces.