I built my standpipe using 24" concrete pipe 4 years ago. So far no issues. I formed and poured a concrete basin for the bottom of the standpipe to transition to the horizontal barrel pipe.
Laid down a butyl rubber rope type gasket and set the lower 8' standpipe section.
After the first section was set I filled the joint hub with hydraulic cement and backfilled and compacted in 8" lifts to the top.
Then I repeated the process with another 6' section. That's the top just high and right of center in the photo.
If I had to do it over the only thing I would do different is make the socket on top of the basin 4-6" deep instead of only 2".
Hope this helps.
