6121 Keying concrete slab surfaces to receive bonded applied trowelled coatings (2) Keying the surface of set concrete slabs prior to the application of bonded trowelled finishes 6122 Cementitious trowelled coatings to floors (88) A surfacing of cement and sand, concrete, or granolithic, including any additives, laid on concrete floor surfaces which have set, either mechanically bonded or unbonded, finished to an even surface,smooth or textured, as a finished surface or as a substrate for other floor finishes 6123 Cement-bound terrazzo to floors (0) Marble and other aggregates with a cement binder, laid as an in situ topping to floors, bonded to or isolated from the substrate, including carrying up against vertical surfaces as skirtings, ground to a smooth or polished finish 6124 Resin-bound terrazzo to floors (7) Marble and other aggregates in a synthetic resin binder, laid as an in situ bonded topping to floors, including carrying up against vertical surfaces as skirtings, and ground to a smooth or polished finish 6125 Trowelled bonded surface coatings to floors (112) Flooring material comprising bitumen emulsion, synthetic resins, rubber-latex, synthetic anhydride, magnesium oxychloride, etc., mixed with aggregate and with a setting agent if required, bonded to the substrate to form a finished surface or as a substrate for other finishes 6126 Mastic asphalt finishes to floors (0) Mastic asphalt applied to floors as a surface finish