Non-slumping, pumpable castable and method of applying the same

An essentially non-slumping, high density, low moisture and low cement sprayable refractory castable composition which can be applied without forms with a density of at least 120 pcf, consisting of a tempered, pumpable first component consisting essentially of a refractory aggregate, a calcium-aluminate cement, a solid flow aid, a deflocculating agent, and water, the water being present in the lowest amount sufficient to achieve a pumpable consistency of the tempered first component, and a flocculating agent as a second component to be added to said first component at time of installation in an amount sufficient to prevent slumping when applied without forms and maintain the castable dried bulk density of at least about 120 pcf.