Limestone is graded according to nominal size; smaller numbers indicate a larger particle size, and bigger numbers indicate smaller stone. Sizes larger then 4” to 6” are denoted by names like Rip-Rap and Gabion stone.
Crusher Run products contain all sizes smaller than their name specifies; 1-1/2 inch Crusher Run has a maximum size of 1-1/2” and about 35% smaller than ¼”.
Sizes smaller than ¼” are referred to by the number of openings per inch that they will pass thru; a ¼” size is a #4, a 1/40th” is a #40 and a 1/200th “ is a #200.
AASHTO, the American Association of State Highway and Transportation Officials, specifies many standard sizes of crushed stone used by many state DOTs. They are specified by numbers, such as #1, #2, #57, #9, etc. but are very different from screen size specifications openings per inch mentioned above. Typical uses for AASHTO sizes are:
#1, #2, #3, #4; Used around construction sites, logging sites, farms, and muddy areas as a base course for roads. These sizes do not grade smoothly, and may be difficult to walk on. A smaller size is typically used to finish the top surface.
#57, #67, #7; Used in concrete and asphalt, septic and drain fields, under concrete slabs, and for backfilling free draining, non compacted applications like basement walls.
#8 and #9; Used for surface treating asphalt roads, abrasives during snow and ice in winter, pipe bedding, and to provide a smooth surface. Not as stable as larger sizes.
Manufactured Sand ; Smallest available, it is crushed sand rather than naturally occurring like in a river or at a beach. Two kinds are available, the C33 Specification is for concrete and asphalt, and the non spec sand is for bedding, agricultural use and fine grading.
Crusher Run, #”, 1-1/2”, ¾” and ½”; All contain a top size as indicated, down to very fine sizes. When properly compacted, these materials provide a smooth, dense, durable surface. These sizes are used principally as road surfaces and shoulders and finished grade construction surfaces.
Rip-Rap and Gabion; Used for slope protection and landscaping, sizes up to 36”
Coarse Ground Agricultural Lime; Air classified, 85% min CaCo3 Equivalent