Sounds like you may be referring to colored conrete, pattern stamping, surface treatments, or finishing techniques that enhance the visual appeal of the concrete.
The supplier should batch the concrete with less than than the maximum w/c required so that their is water available for slump adjustment. If this is not possible consider the use of a superplasticizer to increase slump. ACI-305 and ACI-306 should be of some help as far as slump adjustments are...
