AASHTO #57 Stone Specs - Capitol Flexi-Pave
AASHTO #57 Stone Specs. AASHTO #57 stone as defined by quarries, state agencies, etc. is an open-graded, self-compacting aggregate blend of size 5, 6, & 7 stone. This material cannot be 'compacted' in a true sense, but can be properly oriented with compaction equipment. This is particularly important when using #57 stone under Flexi-Pave surfaces.