New Driveway Question

I'm looking to see what everyones' experience is on putting down 3" rock as a base for a driveway or parking lot then putting 3/4" rock over the top of the 3".

We put in a driveway 19 yrs ago and I was told by some one who use to put in driveways and he told me not to put 3" rock in because it will work to the top. I listened to him and so glad I did. We haven't had to add any rock all these years.

I'm just looking for what your experience is not your belief...

Yes thats what happens with the big rock stay with the 3/4

I really think it depends on soil. I used large septic rock for base on muddy stick to your boots clay. It packed in the mud and stayed put.

I used #8 white rock on Sandy soil. A heavy trash truck constantly made ruts. I wish I had used larger rock.

Another drive I used #8 gravel over sand. No heavy trucks just pickup. It packed in. Made good drive.

So best answer to your question is depends on soil and how heavy trucks are.

The best and cheapest thing I have found is to use slate or shale stone if it available in your area. I get it from the quarry for a couple of bucks a ton. It just overburden in there way to get to the limestone. The large flat pieces make a heck of a base and then cover it with #5 stone.

Well...

We have high organic matter top soil over 150 feet of yellow and blue clayish soils that hold water.

It is -real- hard to get a stable base here.

I agree the 3 inch rock (crushed concrete in my case) does come up a bit.

But, 3/4 inch rock doesn't hold up to traffic in front of a machine shed, tractors and combines and such. It would sink in in 1.9 years, not 19 years.... Even with fabric down, the clay just gives way like pudding and the gravel would push down and sink fabric and all. The clayish subsoil is not stable especially with our heavy snows, deep frost, and spring wet thaw.......

So, what are you going to do?

Deal with a few 3 inch rock coming up, and have a parking area in front of the shed.......

The clay can make a great roadbed if you elevate it 5 feet and crown it, then it sheds water and becomes a hard tough dry roadbed, but that's not practical for a private driveway or parking area in many cases.

Paul

When I put in 600' of driveway through what was a muddy farm field, I took out the topsoil over what is about 3' of sand, then clay below that. The first 300' I put down 6 in of 3" crushed concrete then 6 in of 3/4"-1" CC over that. The 3" wasn't available when I did the next 300' so I just put down 12 inches of 3/4-1" CC. Been about 12 years and both sections have held up about the same. No big stuff moving to the surface. I regraded the area to create ditches alongside of the d/w and I ran them to a creek. I also crowned the d/w. The key is to keep the water from standing. There are a couple of small spots I need to fix as puddles are starting to form and those area are a little soft. Would not do the larger CC again as you get pieces with reinforcing mesh still in it that is just looking for a tire.

We put our driveway in 36 years ago . I dug out top and sub soil which was about 3 foot. I then put the concrete staves of one silo and the two pads that my mobile home set on along with all the field rock we had piled around farm. I put 3" limestone over that and 3/4" to fines over the 3" rock. 22 years of the 36 we truck gardened and had a lot of traffic over it and the picture was taken a little over a year ago and none of the 3" rock has come up and drive way has never been graded.

I wouldn't recommend the cobble, maybe two's and three's, but the biggest bang for your buck will be soil stabilization fabric under whatever you use.
Pete

Fabric (ground cloth) then dirty limestone (53's or 73's) then a thin layer of clean rock. I prefer 11's for my top coat but unless it is good and flat they will be gone the first rain storm

Crusher Run (Item #4) is what its called around here, its a composite mix of crushed stone and fines with a certain size passing through a sieve, 3/4" if I recall. This material is NYS DOT approved sub-base for roads. Depending on your ground conditions, it may be all you need, grade and compact in 12" lifts over existing if its suitable. For larger/deeper fills, there are lots of types of run of bank gravel you can use before topping off with crusher run for either a wear surface or sub-base for some kind of pavement ie; bituminous asphaltic concrete, (asphalt paving) or say concrete itself.

Key things are drainage, determining if existing undisturbed is suitable to build up on or you need stabilization fabric to overcome existing conditions etc.

Clean 3" stone with no other sieve size passing through, just the 3" stone, is not going to compact because you need an array of aggregate/fines to achieve that with optimum moisture levels. Same is true with fine sand, it can be settled with water but you you would never build a pad for a slab or use it for a sub-base for a driveway, again it needs a composite amount of various sieve size aggregate with optimum moisture to compact and be able to support the intended loading properly.

Stick with what has worked good for you in the past. If you didn't use small rock the first time around and it's held up, do that again.

It's all about the soil. In your case the 3" rock would probably work up through. Other places need it.

.

I'm just looking for what your experience is not your belief...

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I have always used the 3" as a base and then used what the crusher calls 2"minus on top. It's a blend that is everything from a powder up to 2". It will set up almost as hard as concrete. There might be a 3" rock come to the top once in a while but not often. I've tried the smaller sifted size and it's a constant job replacing what washes down the hills.