AASHTO #57 (coarse aggregate stone has 100% passing 1-1/2″ screen, 95-100% passing 1″ screen) is an open-graded, self-compacting aggregate blend of size 5, 6, & 7 stone. … Using compaction equipment, #57 stone will typically compact about one inch in vertical height, which is equivalent to about 8% settlement.

What stone is self-compacting?

Clean gravels and crushed rock are sometimes referred to as “self-compacting,” meaning that if they are dumped in beside a pipe, the material will have a high density. Owners, engineers, contractors and inspectors have been known to use this expression.

Is 57 stone a coarse aggregate?

16 sieve—0 to 5%; No. 50 sieve—0 to 5%. So all this simply means that a #57 stone is a coarser 1½-inch-minus graded aggregate and #89 gravel is a finer ½-inch-minus graded aggregate.

ASTM has created a numbering system to classify rocks and crushed stone based on its size. ASTM number 57 stone is large enough to allow drainage while supporting asphalt and cement. It is used in road beds, foundation beds and gravel walkways.