I thought that you were going to say that you got in the car to move it back, and instead drove forward knocking the bike over.
All you got to do to clean this up is pour dawn liquid detergent on it, let it sit over night, rinse it off in the morning with a garden hose and it will be totally clean.
Try washing with gasoline and putting oildry to soak up the gas. It may have already soaked into the concrete. Oh, bytheway I ran over a brand new brake booster one time. Decided I'd pull the truck inside but forgot that I left the booster under the front wheel. My boss sent it back, Defective. He was sorta shadey.
Welcome to the "Mr Lucky" club Club symbols- Snake Eyes
#13
Black cats
8 ball