In standard industrial cases full strength concrete is recognized at 28 days.
Roof slab curing time.
At this point the neighborhood dog will not leave his footprints in it but you should keep it clear of heavy equipment during this time period.
Ideally the slab could be water cured for 7 days some builders on a tight schedule water cure for 3 days as this achieves approximately 80 of the benefit of water curing for 7 days.
Vertical retaining wall or plastered surfaces or concrete columns etc.
Pavement slabs roof slab etc.
Curing time for concrete.
The removing of shuttering related with span of the roof slab.
Are covered under water by making small ponds.
The precast concrete items are normally immersed in curing tanks for a certain duration.
21 days for underside of beams arches above 6 meter span and up to 9 meter span.
48 hours for sides of foundations columns beams and walls.
Water curing can be done after the slab pour by building dams with soil around the house and flooding the slab.
But to answer the question of how long does concrete take to set concrete setting time is generally 24 to 48 hours.
The indian standard is 456 2000 recommends that curing duration of concrete must be at least seven days in case of ordinary portland cement at least ten days for concrete with mineral admixtures or blended cements are used.
Are cured by spraying water.