There are a lot of things that factor in when curing concrete Heat, humidity, sub surface, ground water moisture, and what "recipe" of concrete they poured. If they used a "high early" mix around here you could be on it the next day (more expensive and a little harder to work with). If they used a "Super PSI" it could be as long as 14 days (reasonable cost but lays on the ground wet a long time). If the used a standard "2500 PSI" and poured it at a 4 inch slump, I would suggest 5-7 days at 50 -70 deg with reasonable ground water content (no standing water if dug 1.5 foot below bottom of slab poured).
Many factors come into play here it is best to ask the contractor and call the redi mix plant and ask them as well.
