1.1 ,This classification covers fireclay and high-alumina plastic refractories and ramming mixes that can be pounded or rammed into place to form a monolithic structure. The terms “,plastic”, and “,ramming mix”, are generally intended to describe the workability of the material. In this regard, plastics are considered to be materials having a workability index of more than 15 ,% in accordance with Test Method C181, while ramming mixes generally have less than 15 ,% workability by the same procedure.