On curing of cement..

We did casting of our RCC roof. Watering was done about 15 hrs from the time the concrete was laid and for the portions cast in the initial hours, it was almost 22 hours when it got watering.. Is this ok ? For how many weeks, the RCC slab need to be watered/kept wet/covered by water for getting maximum strength and to avoid leaking.Hariharan, Cochin, Kerala, India