Note: The ambient Temperature is a factor to take into consideration when calculating drying times
Concrete doesn’t gain strength by drying, but by “curing” which it does for the period while it remains damp after laying.
A 100mm thick kerb take approximately:
1 day to achieve around 30% of its full strength.
At 2 Days it passes the 50% mark.
And at 3 Days 75% has been achieved.
It takes concrete approximately 30 Days to reach 99% of its final compression strength.
The thickness of the concrete will of cause affect the curing times.
I.E. The thicker the longer it will take.
Its a good idea is to keep the concrete damp while it cures, you can place a sheet of polythene over it. You can also spray water on it with a hose if you want to.
Note; If you can keep the concrete damp for a week or more, it will have a higher compression strength.
Protect the concrete from hot sun for the first day (in some countries they don’t lay concrete until the afternoon to avoid the hot mid-day sun which causes cracking and dusty/flaky surfaces).