Descrete or "DES-CRETE" is a material that can be mixed with Portland cement and poured below the floor of an oven to insulate the oven floor.
Descrete comes in 25 pound bags - part number 9-171149.
The quantity of Descrete required is approximately 2.5 pounds per square foot per inch thickness.
Typically Descrete is poured 3 to 4 inches thick.
Attached are instructions for mixing and curing "DES-CRETE" insulating floor material.
Also attached is the safety data sheet.