Graded Base vs. straight stone Dust on roadway/driveways

[Red Horse]

Point of clarification, "Graded base" to me is a mix of crushed stone and the resultant fine "dust". "Dust" is just that-only the fines, without any crushed stone. GB is typically sold around here with either 3/4" minus stone or 1-1/2" minus stone mixed with dust

I've always used graded base to dress up my drive, (as well as neighbors common drives) but I'm thinking, perhaps a top pass with just dust might provide for a smoother job. One of my neighbors had a contractor regrade his last year ("theirs"-2800' long serving six houses) and the contractor built uo one stretch using 1-1/2" minus-bad choice-rough as ****. I'm redoing that same drive now and got the idea , might be better off to finish with just dust.

Any oipinions? Best bet would be to rent a vib roller but they don't want to spring for t hat

 

[byronlj]

I put 3/4 crushed on my red clay soil right after the monsoons soaked it. Neighbors have large service vehicles which packed it down real nice. I still have some loose 3/4 on top but the road is nice and smooth. It also handled the winter snows just fine.
Dave

 

[vtsnowedin]

Depending on the source rock a layer of just dust will most likely turn to wet snot when it rains. The 3/4 minus stone run over a screen to remove the dust and then blended to clean sand in the right proportions is the way to go. The sand can be washed or from a river or glacial deposit as long as it is less then 12% silt (Dust passing a #200 screen).

 

[s219]

You really need the mix to lock together and form a firm base, so it requires sizing from about #7 on down to the fines (what we call crusher run here). Dust by itself will not lock together, and will be soft and prone to washing off.

 

[Red Horse]

Guys thanks for opinions- one other point. The GB I'm using is made from trap rock-another New England term? Which is a bluestone that is blasted then crushed. Big difference between that and crusher run that is crushed bank run gravel is there is no sand in this stuff. It is the heaviest, most dense product you can get-about 3000lbs per yard.

 

[k0ua]

I am always amazed by all the local names for the various rock products.. Here we use 0 to 3/4. It is limestone that ranges in size from dust (0) to crushed limestone pebbles up to 3/4 of an inch. It makes an excellent packed base.

 

[Browneyesvictim]

As stated road base material is typically 1-1/2 minus or 3/4 minus material, and will have a lot of DIRT in it as well as some crushed stone of varying proportions. Aggregate producers around the country are driven by contract bids to meet certain specifications on the percentages of gradation, flats & elongated, and many other quality properties. What the retail and homeowner often gets is from the reject pile that has not or will not pass lab analysis with no quality control or specific product specification. There my be some oversize material in it, too much clay, and so on... Even most of the state spec road base allows too much dirt and fines for my taste. Personally, I like to put down 1-1/2 minus base material as a base on a new road (or after scarifying and grading an old road) to settle in the graded road, then cover layer of 3/4 "open" which should be nothing but 3/4" crushed stone. If you wanted something real fancy to finish that further you could put 1/2" or 1/4" chips on top of that. Those crusher chips are the high value product typically used as asphalt material and concrete/masonry materials that will cost a LOT more $$$

So in summary, I would check out the source of the rock you are getting. Call up your local quarry. You will likely get it cheaper anyway, and talk to the production supervisor what exactly is available, and look at the product piles. You shouldn't pay the same price for the spec base material as the "reject" material, but is often the case.

I hope this helps... Lets just say I've been in just a few quarries, and I might know a thing or two about rock crushing and screening... ;-)

 

[vtsnowedin]

As stated road base material is typically 1-1/2 minus or 3/4 minus material, and will have a lot of DIRT in it as well as some crushed stone of varying proportions. Aggregate producers around the country are driven by contract bids to meet certain specifications on the percentages of gradation, flats & elongated, and many other quality properties. What the retail and homeowner often gets is from the reject pile that has not or will not pass lab analysis with no quality control or specific product specification. There my be some oversize material in it, too much clay, and so on... Even most of the state spec road base allows too much dirt and fines for my taste. Personally, I like to put down 1-1/2 minus base material as a base on a new road (or after scarifying and grading an old road) to settle in the graded road, then cover layer of 3/4 "open" which should be nothing but 3/4" crushed stone. If you wanted something real fancy to finish that further you could put 1/2" or 1/4" chips on top of that. Those crusher chips are the high value product typically used as asphalt material and concrete/masonry materials that will cost a LOT more $$$

So in summary, I would check out the source of the rock you are getting. Call up your local quarry. You will likely get it cheaper anyway, and talk to the production supervisor what exactly is available, and look at the product piles. You shouldn't pay the same price for the spec base material as the "reject" material, but is often the case.

I hope this helps... Lets just say I've been in just a few quarries, and I might know a thing or two about rock crushing and screening... ;-)

That's pretty much the long and short of it. I can tell you're BTDT.

 

[Red Horse]

As stated road base material is typically 1-1/2 minus or 3/4 minus material, and will have a lot of DIRT in it as well as some crushed stone of varying proportions. Aggregate producers around the country are driven by contract bids to meet certain specifications on the percentages of gradation, flats & elongated, and many other quality properties. What the retail and homeowner often gets is from the reject pile that has not or will not pass lab analysis with no quality control or specific product specification. There my be some oversize material in it, too much clay, and so on... Even most of the state spec road base allows too much dirt and fines for my taste. Personally, I like to put down 1-1/2 minus base material as a base on a new road (or after scarifying and grading an old road) to settle in the graded road, then cover layer of 3/4 "open" which should be nothing but 3/4" crushed stone. If you wanted something real fancy to finish that further you could put 1/2" or 1/4" chips on top of that. Those crusher chips are the high value product typically used as asphalt material and concrete/masonry materials that will cost a LOT more $$$

So in summary, I would check out the source of the rock you are getting. Call up your local quarry. You will likely get it cheaper anyway, and talk to the production supervisor what exactly is available, and look at the product piles. You shouldn't pay the same price for the spec base material as the "reject" material, but is often the case.

I hope this helps... Lets just say I've been in just a few quarries, and I might know a thing or two about rock crushing and screening... ;-)

Browneyes,
Trust me. The product I'm talking about has no "dirt" in it. Strictly shot trap rock that has been run through all the various stages. The process is not exactly scientific once the respective materials come off the conveyors-i.e. 1-1/2" one stack, 3/4" another stack, fines another stack. In the quarry I usually pull from they have a new 980 Cat that charges the asphalt plant, the concrete plant, and loads the will calls such as myself- he loads my single axle B-61X very carefully!
This operator in his "spare time", "makes" graded base products shuttling a bucket of stone then a bucket of dust while working the pile from time to time to insure a reasonable blend. Again here in Mass, this is graded base. Almost 50 years ago as a college kid in Connecticut I hauled the same stuff-except in Conn they called it "Process". and to this day that is what it is still called in Conn. By the way, in this neck of the woods, all the big independent outfits are just about gone. Most of the Northeast is controlled by the Irish companies (Old Castle, Tilcon etc) Same on the west coast?

One other point on your "dirt" comment. Graded base here is typically traprock based. You can get a GB that is referred to as "Borrow Products" or "brown base". I think that is the stuff that is basically bank run gravel that goes through the crusher-and would have "dirt" in it.

Back to my original question, your suggestion on 1/4 chips is probably a good one-but probably too pricey for my neighbors. I probably should convince them to let me rent a vib roller to pound the 3/4 in. In any case I just might treat one section with dust and see how it holds up.

In any case thx for everyone's comments. Attached are a couple of shots I took today

 

[GLyford]

Where I live now and where I grew up most of what was in the pits was/is granite. My Dad and brother put in a driveway of just stone dust a foot deep that held up very well for 20 years (it was paved over after that). If your traprock is similar to granite, I could see just dust working well for a "top dress" over the existing base. It would be easy to spread, and as long as you kept at least a slight crown I don't think water would be a big problem...?