Re: Silicone caulking to keep ants out??
It would seem that ants could use the bees entrance, so caulk seems unlikely to stop ants.
But you can stop ants by isolating the support for the hive, unless you have ants that fly!
If your hive (or stand) has legs, put those legs in a pan of water or oil. If it sits on blocks, devise an alternative method with short "legs". Perhaps use some short pieces of PVC pipe (say, 2-3" tall, standing on end) into 4 tuna cans on the blocks, then set the hive on the PVC. Of course, the PVC needs to be higher than the side of the tuna cans. Oil will evaporate much more slowly than water. I'd try cheap vegetable oil and see how that goes.
USDA Zone 7a - elevation 1400 ft