Compacting gravel driveway

[paulsharvey]

that's what i'm getting. It's called modified in my area. Just thinking about adding more stone dust for better compaction

The ideal product should be pretty evenly graded (sized), from fines (powder) on up to fist sized material. Too "boney" or too much fines are both a negative. I would only consider adding fines if the was a issue, and still, I wouldn't add just fines; I would scarify the surface and add some more crushed rock.

 

[LouNY]

When I top dress my driveway I get screened gravel, commonly call #57 or #67 or fine screened. My driveway is too steep for crusher run and fines, the dust gets carried away to easily by the rain and you are left with loose rock.

 

[2manyrocks]

A highly experienced road builder here told me that there is a difference in compaction between two quarries in our area. The material from one of them is more granular and doesn't compact well. The other quickly sets up to a firm consistency.

 

[paulsharvey]

Each real rock mine is going to pull proctors, and there can be a pretty significant difference in results; based not only on the rock, but the crusher, as well as clay content. You can see anything from maybe 108 pcf max density to 125+ pcf max density from mines just a few miles away.

PCF= Pounds per Cubic Foot

Also, some over burden ends up in the rock too, and that affects things as well.

 

[Egon]

Handbook on basic compaction.

https://www.multiquip.com/multiquip/pdfs/Soil_Compaction_Handbook_low_res_0212_DataId_59525_Version_1.pdf

 

[paulsharvey]

I am slightly hesitant to say this, because I haven't used your material; but generally speaking; if you pick up a fist full of material, squeeze it, you Should be able to make a ball that kinda sticks together, but when you drop it, it completely falls apart. If you can't kinda make a ball, then it's too dry; if the ball sticks together when dropped, too wet. Needless to say, this changes based on material type, and this would not apply to a gravel type material.

 

[paulsharvey]

So, AlexinPa, check out "Prices of driveway paving" thread, I tagged you in it. There are literal essays written over there, on driveways, compaction, materials, ect. There are also about a dozen more threads on this specific topic, and way too much to type out on a phone again.

 

[Alan W.]

Ive noticed that road base is called by different names depending on your location.
Here we use DGA which stands for dense grade aggregate. If you want to get a high level of compaction then you get DGA that has been run through a PUG mill. This is basically mixing water into the DGA. This mixture will compact like concrete.
All rock in our area is sold by weight and the price varies by the size.

I sure prices are up some this year but these prices were good this spring.

I am not sure of your existing drive but when building a road you first cut out all the organics, meaning the topsoil is removed to the clay. Fabric is laid followed by #4s then the DGA. This is an over simplification of the process and doesn’t address drainage.

 

[dodge man]

A couple of more useless tidbits on compaction. Most of the time the actual strength of the compacted material isn’t important. The goal is to compact it so it doesn’t settle. Even under buildings the actual strength isn’t that critical unless it drops below a certain threshold, than something needs to be done, such as wider footings.

My biggest problem with my gravel driveway before we paved it was it turning to soup when the frost left the ground in the spring. If you get a good solid base going you can top it with something like chips which won’t compact but will be cleaner.

 

[paulsharvey]

What I think causes a lot of problems with these things, step 1; define the scope/goal/budget, and then work from there.

What I mean is, function vs pretty; the $2000 fix or the $20,000 fix, are we wanting are low clearance corvettee to stay clean and not rub, or are we driving a suv/truck. I really think your material will be 100% fine, exactly the way you planned it, and I think adding additional fines is an unneeded expense, and could possibly make the material worse, dustier, and more prone to washing. It would, however, probably improve ride quality and appearance.