The following table presents the minimum time requirements before removing the formwork. It regards typical constructions for usual temperatures:
Constructional elements 
Cement strength category 

32.5 
42.5 
52.5 
Lateral sides of beams’, slabs’, columns’, shear walls’ formworks 
3 days 
2 days 
2 days 
Slabs’ formworks and beam span formworks when the span is lesser than 5 m 
8 days 
5 days 
4 days 
Slabs’ formworks and beam span formworks when span is equal to or greater than 5 m 
16 days 
10 days 
8 days 
Safety columns of frame beams and slabs with a span greater than 5 m 
28 days 
28 days 
22 days 
Nowadays, cement with 32.5 strength is usually the cement that comes in sacks. On the contrary, the cement used by most concrete production industries usually has strength equal to 42.5.
When removing the formwork of slab or a beam 5 days after concreting and intending to cast the next floorwhich means doubling the loads applied to the floor without formwork  supporting scaffolds (falsework) must be placed beneath the formworkfree floor. This problem is much more critical in cantilever slabs.
It must be mentioned that there are a lot of exceptions to the above summarized rules where the suggested limits of most issues may be exceeded. However, in every case the supervisor engineer is responsible for satisfying the general or special specifications of the work.