is it inside or outside? out side use cement, inside epoxy and chip...it was hand troweled in then they use carbide stone to grind in the curve..we have done some of these, on outside steps i have recipe for portland that lets us grind and reseal the next day. we colored it with oxide, i used a pencil grinder and some round stones i got at the hardware store for $2 each...not that hard...that might have been a precast step done at a factory with those bands.  epoxy wont work outside though...inside i would just use akemi and add black stallion chips.