grading driveway

[ruffdog]

I have been lurking on this forum for a while and a happy BX1880 owner. I am now considering a larger piece of property and coincidentally many of the posts I have read reference grading a gravel/dirt road. I would be grateful if anyone could advise how much gravel needs to be added to virgin clay to make a dirt road.
cheers
Beardy

Are you where the ground freezes and thaws? What would be the largest load driven on it? How often?

Around here, if you want a gravel drive to support a concrete truck when the frost is coming out, you need a good base. That means digging out some soil, 12" of rolled 4" rock, some 2" rock, and some 3/4" stone and dust. Like other's have said, make it high enough so water can run off.

 

[sdef]

Another vote for adding a layer of material, working it in and seeing how it works. I built my new driveway and retirement home located in SC in 2014. My soil is clay and very rocky- finger sized to 3' in diameter- like mountain property with the driveway on a moderate grade. The property is densely forested with large hardwoods and a few pines. Removing the trees left large holes to be backfilled with existing rocks and clay, also with large rock removal and backfilled; when completed it was quite a mess, especially when it rained.

I then had 3/4" - 1-1/4" steel slag (less expensive than gravel/crusher run and works great) delivered and spread ~3" - 4" deep with the intent of home construction traffic packing it for me- which worked as expected especially during the rainy season. Once a year over the next two years I had more slag delivered/spread ~2" depth during the rainy season that packed through normal use. Now I have a surface that is very hard with 90% of the slag compressed into the clay and a very hard surface that never ruts. I lightly groom part of it once or twice a year with a tractor rake due to a few spots of small depressions in the surface I did not fill deep enough initially which are also impacted by tree roots from large oak trees I did not want to harm.

This method worked well for my circumstances. The only thing I would do differently would be to pay more attention to the areas around the tree roots.

 

[pacosperson]

I have been lurking on this forum for a while and a happy BX1880 owner. I am now considering a larger piece of property and coincidentally many of the posts I have read reference grading a gravel/dirt road. I would be grateful if anyone could advise how much gravel needs to be added to virgin clay to make a dirt road.
cheers
Beardy

The US Forestry Service has a GREAT booklet, 93 pages as I recall, about creating and maintaining gravel roads of all types. From heavily traveled by the public to very rarely used by anyone in the deep woods. Look it up, they'll provide you with excellent advice.

 

[ruffdog]

This it?

https://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprd3793545.pdf

 

[charlessenf]

I would be grateful if anyone could advise how much gravel needs to be added to virgin clay to make a dirt road.

I had a similar situation here in NC and found opinions varied, to put it kindly. In response, considering the price of rock, I contacted the state roads people since they wind up maintaining roads as well as building new roads (paved and otherwise).

Turns out, they are civil servants and have Manuals to guide them in requesting bids and such. The guy I hired will likely go to his gave swearing the ABC (small rock) goes down first.

But the 'experts' paid to maintain roads by everyone with a license plate, agreed with me that the larger "Ball" rock (3" or so) went down first, then the ABC or similar.

The manuals had details on shoulder, slope, drainage etc. And, in my case, they were accessible online.

and "If I did it again I'd add geotech fabric as the first layer." Good Point

 

[2manyrocks]

My neighbor has a ridiculously steep driveway that was bulldozed through red clay. We put larger rock (1-2") down which seems to be holding pretty well for him. If we had used smaller rock, I think it would be less resistant to washing and would have been more like a bunch of marbles when it comes to driving uphill on it.

Given the cost of gravel delivered these days, a layer of geotextile fabric might help avoid the need to add more gravel later due to it sinking into the ground over time even though the fabric adds some up front cost.

 

[rocco611]

USFS and other agencies have documents you can find online that provide great engineering information regarding roads. Some are by region, so look for publications that deal with your area and soil type.
I put in 300' of driveway on expansive clay soil when I built my house 15 years ago. Drainage is especially important with clay soil, I built up the driveway with the clay topsoil, graded it so it would drain. then added 4" of crushed rock road base. After a few rains and compaction from traffic I added another 4" of road base. It is now a solid surface that doesn't require much maintenance.

 

[beenthere]

As mentioned, first grade the location of the new driveway so water is drained away, with enough slope that no water is standing in the side ditches. Put a crown in the drive so the water runs off to the side.

 

[etpm]

Since I don't have clay but instead sandy loam with a lot of clay mixed in my situation may be similar. About 15 years ago when we first put in our drive I used a bush hog and my Ford 9N to blaze a trail through the woods. Then the dozer came and made a road. On the advice of the guy, who was also a neighbor, who would be bringing in the gravel and actually making the road I put down about 6" of railroad ballast. This stuff was left in place until the house was done. Then 3/4" minus, about 4" worth, was spread over the ballast rock. Since the original road went in we have had to add gravel twice. The first time, about 5 years ago, the wrong gravel was put down by a shyster gravel company here on the island. The stuff was too small and the wrong shape, so it ended up sinking down and shifting some. Two years ago we had a trustworthy fellow bring in the correct gravel, 3/4" minus with fines. He laid this gravel down and re-crowned our roads, and compacted it all. The drive now drains properly and not only looks great it drains great. I'm pretty sure the roads on our place will now last a very long time. I'm not sure why I had to add gravel the first time because there was so much stuff already in place but I think it is because the sandy loam and clay mix let everything just sink in. I have wondered, since I read about geotextile fabric here on TBN a few years ago, if that stuff would have prevented my roads from sinking. In any case it all seems stable now.
Eric