Let s Talk About Crushed Stone

[MikeR 2018]

I am trying to understand crushed stone sizes and types but can t find a definitive guide or explanation. I realize that different parts of the country have different quarries so there may be no common definition but I thought it best to ask all of you.

What I know so far:
Gravel is rounded river rocks.
Crushed stone is big rocks that have been crushed to a specific size. Modified means the crushed stone was not washed to remove the rock dust it packs better.

What I DO NOT know
I thought that sizes like 2A meant the largest stone was 2 inches but I may be wrong. The letters confuse me. I hear that 2B is smaller than 2A. Huh?

Some is called AASHTO with a number after it, like AASHTO #57. How does that work?

I need some top dressing for my drive and in front of the barn. Our horse walks on this so the stone needs to be small enough so that it does not get stuck in their hooves.

I may need something for French drains. I assume that is washed but what size?

Finally, what is anything else about crushed stone that you know?

 

[Diggin It]

I've used something known to me as 'Quarter-Zero' which is basically more like very coarse sand. People tell me that if you do it right, well compacted and watered in, it will set up almost like concrete. I used it on a walk path and when I tried to change it later to a poured concrete sidewalk, I had to break a lot of it with a pick-axe. The surface stayed gravel like though with loose but very small stones.


Can't comment on the horse hoof issue.

 

[MikeR 2018]

I've used something known to me as 'Quarter-Zero' which is basically more like very coarse sand.

Sounds nice but I never heard of it. Maybe I can ask my quarry

 

[bcp]

This may help.

Bruce

 

[mikester]

Crushed stone is angular and packs better than crushed gravel.

For drainage you want something like 3/4 clear (no fines), crushed gravel works well for this.

My personal preference for making nice driveways and walk ways is at least four inches of 3/4 crusher run crushed stone topped with one inch of 1/4 crusher run chrushed stone. The fines help it pack nicely, easy to keep smooth and packs like cement - great for cars/motorcycles etc. Sorry I don't know how that would affect horse hooves/shoes.

Ask your local supplier for exactly what the differences are in what they supply.

 

[Shblack]

We have used a couple of products, all crushed limestone:
- Crusher run, which is smaller gravel through limestone dust. Packs well, gives a good driving surface but can be dusty when dry. We put it down when things are wet, then roll it - road surface holds up better
- Float rock - 2-3” pieces, good for a road underlayment, French drains
- Rip-rap, typically 6” to 12” pieces, good for stabilizing creek banks or controlling erosion
- Shot rock - What gets scooped up after blasting, no crushing, can be pieces >2’, good for fill and creek banks, lowest cost per ton.

When we redid our driveway (runs next to a creek, creek would flow over the driveway and wash it out), we built the level up 18” using rip-rap, then put down 6” of float rock to fill in the gaps between the rip-rap, then topped it off with 6” of crusher run

 

[MikeR 2018]

This may help.

Sure does. Thanks.

I m from Pa so this fits my area. I also work for PennDOT (computers - not roads). I should have looked for their documentation.

 

[Diggin It]

Looks like what we're talking about is their #10 or smaller. Others mentioned 1/4 crusher rock, or crusher run.

 

[Ford850]

Your stone will be similar to what we have here. I'd suggest 57's for the drainage. They are all similar size and no dust. For the drive topping, it depends what you're trying to do. We have what's called 411 size, which is approximately 3/4" down to fines and dust. It packs well and it's what I use for general repair, fill, and topping. If you want a clean small thin top coat, then go for 8's or 9's which provide a nice quiet and clean surface. But they don't pack so they stay loose... use as a thin coat only.

 

[herm0016]

another option, recycled concrete. it's usually cheaper and it packed very well. includes the aggregate and the concrete fines. I find it strange that each region has its own names for different grades / sizes of gravel.