Green concrete should not be exposed to the sun until after it has
been allowed to set for five or six days. Each day during that period
the concrete should be wet down by sprinkling water on it, both in
the morning and afternoon. This is done so that the concrete on the
outside will not dry out much faster than the concrete in the center
of the mass, and should be carried out carefully, especially during
the hot summer months. Old canvas, sheeting, burlap, etc., placed so
as to hang an inch or so away from the face of the concrete will do
very well as a protection. Wet this, as well as the concrete. Often the
concrete Forms can be left in place a week or ten days; this protects
the concrete during the setting-up period and the above precautions are
then unnecessary.