Zero-slump concrete curing procedures are dramatically different from those for cast-in-place concrete. Producers prolong hydration by adding moisture in controlled environments with 90% to 99% humidity. Producers cannot rely on the humidity in the ambient air for the moisture needed for the hydration because production demands force them to accelerate humidification. Pressed by production demands and limited curing space, producers often choose to accelerate concrete-unit hydration by filling the curing room with mists. Installation of misting systems doesn't require major plant revisions. [keywords: mist, curing, vapor]