Its highly likely the concrete floor will not crack
Concrete floors are very hard to crack
Several options:
1. Drop it from a tiny height.
2. Use very fresh (wet, uncured) concrete without large, sharp gravel.
3. Wrap the egg in very good padding. Several layers of bubble wrap might do, depending on the height.
4. Put everything underwater. The egg will sink very slowly to the concrete.
5. Travel to someplace, like an asteroid, where gravity is extremely weak, and drop it there.
6. Drop a fake, solid egg onto the concretr and when no one is looking, replace it with a raw egg (you need a magician's sleight-of-hand deception skills to make this effective.)
P/S : Good Luck
~Best Best~