Crushed concrete fill:
-max dry density of material < 3/4 inch 117 PCF at 13.5% moisture the standard proctor
-oversize material 20-30% > 3/4 inch
Compaction method:
-probe sub grade and compact if necessary
-compact #57 stone to 6 inches above pipe
- 9 inch lifts of crushed concrete fill
-...
