Spacer wheel
Discovering the true origins of something can be nearly impossible if you don’t know where to begin. Without knowing what to look for, the OP’s search for learning about the origins of this wheel-shaped object came to a sudden screech. So, without wasting time, he uploaded it to r/WhatIsThisThing to let fellow Redditors research for him.
It didn’t take long for somebody to reveal its true origins. This is a simple spacer wheel that construction workers use to keep rebar in place while pouring in concrete. Concrete usually dried around the spacer bar, so finding a used one is quite rare.