Hoo boy, just last week installed a Service to one of these. Finding enough "meat" and long enough Tap-cons proved to be a major challenge in hanging the meterbase and panel, etc.
Some places 3-3/4" tapcons weren't long enough!!!
Ai-yi-yi!
Finally after seeing a cut cross-section of what I was working with, did I understand better of how to fasten things to the stuff!
Haven't got to the rough-in yet, but 1-1/2" 4x4s with 1/2" plaster rings is how I'm going to tackle it...
And a hot knife.
Hebel Block is another trendy building material around here for the birkenstock wearers... Aerated Concrete... Interesting stuff.