The storable, low-density, hydraulically-active, cementitious slurry of the invention is suitable for cementing within a subterranean formation for oil or gas wells. The spacer group can have a length in the range from 0 to about 20 atoms. The assembly is partially shaped to the shape of the mold, and then a remaining portion of the assembly is formed and compacted in a second direction, opposite the first direction, to shape the assembly completely to the shape of the mold.