Pull up to any quarry between Chattanooga and Ringgold and the price sheet on the office wall reads like a foreign language. Crusher run. ABC. #57. #4. #8 screenings. If you're trying to order material for a driveway or pad and you can't tell those apart, you're going to end up with the wrong thing in your yard — and a truck driver who's already gone.
Here's the plain-English version of what those numbers and acronyms actually mean.
Quarried limestone is run through a crusher, then screened through a series of sieves. The "number" of a stone refers to which sieve size it falls through. Bigger number generally means smaller stone, with a few exceptions. The Tennessee DOT uses sizing similar to AASHTO standards, and most local yards around Hamilton County and North Georgia speak the same vocabulary.
A clean stone is one size with the fines (dust) screened out. A graded stone — sometimes called dense-graded — keeps the full range of sizes from coarse down to fines. Fines are what let a base lock up tight under compaction; clean stones drain but won't bind.
Crusher run is the catch-all term for dense-graded base stone. It's everything that comes off the primary crusher, fines and all, with a top size usually around 1 to 1.5 inches. Some yards call it "minus" material — for example, "1-inch minus" means everything from 1 inch on down.
This is the material that goes under driveways, building pads, and concrete slabs as a base course. Spread it, compact it with a roller or plate compactor, and it locks together into a stable platform. Without the fines, you don't get that lockup.
ABC stands for Aggregate Base Course. It's a spec, not a single product — it defines a gradation curve the material has to fall within. In practice, ABC and crusher run are often the same thing or very close, but ABC has tighter quality control because it's used on road bases. If you're building a driveway you want a contractor to warranty long-term, ABC is the cleaner choice. For a pasture road or a temporary work pad, plain crusher run is fine.
#57 is a clean, washed stone roughly 1/2 to 1 inch in size. No fines. It drains aggressively and doesn't compact into a hard layer — pebbles roll under your feet. That makes it the go-to for:
A common mistake on driveways: ordering #57 because it looks "clean" and pretty. It does look great fresh — and then ruts under tires within a season because it never locks up. Use it where you want water moving, not where you want a stable surface.
For a residential gravel driveway on a sloped lot in Signal Mountain or Soddy-Daisy, the usual recipe is 4 to 6 inches of crusher run compacted as the base, then a 1 to 2 inch topping of #57 or #67 if you want a cleaner look. For a building pad supporting concrete, see our building pads pillar — gradation and depth matter even more when a slab is going on top.
If your project involves footing drains or a wet area, you'll want clean stone, and you'll want to coordinate with the footings and drainage work so the right material lands where the trench is open.
Not exactly. "Gravel" is a loose term most folks use for any small stone. Crusher run specifically means crushed quarry stone with fines included, sized for use as a compactable base.
You can, but it won't hold up well to vehicle traffic alone — it stays loose and ruts. Most driveways perform much better with a crusher run base underneath.
A common range is 4 to 6 inches of compacted crusher run for residential driveways, with more depth where soils are soft or where heavy trucks will run.
ABC is a graded spec with tighter quality control, typically used on roads. Crusher run is a more general term for the same kind of dense-graded base material from the crusher.
Most material around Hamilton County and North Georgia comes from regional limestone quarries. Yards along Highway 27, Highway 153, and the Ringgold corridor commonly stock the gradations above.
