The slab may not be drying out for any of several reasons: geographic location, when the slab was poured, HVAC hasn't been turned on, or the room is colder than the slab. You may want to look into moisture mitigation. However, this can be time-consuming and costly.
To find out what can be done, please see 8 Reasons to Turn on Your HVAC. For more information or call (844) 829-3335 to talk to a professional.