Given the image above: What should I use to backfill the hole around the concrete pier block?
I am thinking to use one of the following:
(1) Paver base (again)
(3) Just the dirt that I dug out of the hole
(4) Concrete mix.
I would not have used clear stone under the block as it doesn’t compact properly and doesn’t look like you have any drainage for the water. This may cause a freeze/thaw condition that could lift the pier. Now I would backfill with a binder like screenings and compacting that will help to compact the stone. Then top off with topsoil if you want grass or original backfill material. You may have to top up with soil again as it compacts.
If this is going to have pedestrian traffic around it, I would fill with the dirt you excavated and let the grass grow to the edge of the concrete. This will be aesthetically best and also stabilize the moisture level under the block.
Are you going to remove the excess sealant? Did you drill and set the post base in a preformed block?