A little more expensive than concrete.
Definitely more convenient.
Utility companies switched to this years ago.
(different formulation obviously, but still expanding poly foam)
I have only used for mailbox, worked fine.

[Linked Image from i.postimg.cc]

Roy

What this world needs is a few more Rednecks.

The Dildō Of Consequence Rarely Arrives Lubed

Waterboarding isn't illegal if you use diesel