crown on driveway

[cisco]

I'm prepping out a single lane (15' wide, 3' shallow ditches on either side) 1000' dirt driveway on which I intend to place gravel. The dirt alone was adequate for infrequent personal use, in that I've only once in 3 years had to box blade a few loads of extra dirt on it to fill the shallow tire track grooves. However, a contractor is building a garage/apartment on the property in a few months, and that will mean a bunch more, and much heavier, road traffic - and once the abode is constructed, more frequent visits to the property by me. So, I'm going to apply Roundup and put a nice crown (again) on the driveway, and then gravel it once before the construction, let the trucks pound the new gravel into the roadbed, and then gravel it again. In theory, this should work - but probably won't, given my luck.
Anyhow, what sort of drop-off between the crown and side of the road should I shoot for, and does being a dirt/gravel road make any difference (vs. the current dirt alone)? And, as long as folks are feeling generous with advice, what size gravel should I use for the first and/or second applications?

 

[Slamfire]

I do about 3" between the leading low edge of my blade and the high trailing edge, that seems adequate for this hard southern clay. I do have some problems with the shale that is underneath on reverse camber curves, in that I can't dig low enough to tilt the road the right way.

 

[accordionman]

SIR,
i would suggest you use gravel that is large for the first
time. it will go into the driveway, if there is heavy traffic,
and then you can use something smaller.
i had a problem in front of my place, and used 2inch clean
to start with. it disappeared, and then i had another load
on top of that. then i used 3/4 inch to top it off. it made a
good hard surface to drive on.
accordionman
william l. brown
wright city, mo.

 

[JohnMiller3]

</font><font color="blue" class="small">( what sort of drop-off between the crown and side of the road should I shoot for )</font>

Rule of Thumb: ½” per roadway foot from crown to edge of road (not including road shoulder)

Ex. 15’ wide road, with crown in center, with 7 ½’ feet per roadway side = 3 ¾” rise over 7 ½’ from shoulder edge to crown center (or approximately 4 %)

 

[cisco]

Got it. Thanks folks. Now, if that hurricane currently churning in the Atlantic doesn't come my way (coastal South Carolina), maybe I can make some progress next weekend. I've finished a weekend of bush hogging, and have switched over to the box blade.
Speaking of which, boy am I dumb. I had dropped the box blade on some uneven ground a few weeks ago (stupid trick #408 - don't ask about 1-407), and when I tried to put it back on the 3ph I couldn't simultaneously get both lifting arms aligned with the pins on the 500 lb plus box blade - until, and this took 15 minutes to figure out (during which I was sweating with a crowbar and hammer), I remembered that 1 of the 2 lifting arms was adjustable. DUH!

 

[Slamfire]

Oh, that fact could make my life easier. /forums/images/graemlins/wink.gif

 

[Soundguy]

</font><font color="blue" class="small">( what sort of drop-off between the crown and side of the road should I shoot for )

Rule of Thumb: ½” per roadway foot from crown to edge of road (not including road shoulder)
)</font>

That would be great on a hard surface road that is shedding water.. gravel is so porous that water will be traveling beneath the substraight... it will be like an aquifer... I'd go flat.. besides.. it'l crown on its own with traffic.. and he'll have to blade that out as well.

Soundguy

 

[CTyler]

We used 3" crusher run spread flat, it crowned itself. Actually needed to drag some from the middle to the edges several times. We still need to top it but have been waiting until the heavy trucks like cement, lumber, septic, etc.. are all done, almost there!

 

[PaulT]

I would strongly suggest that you DO crown the roadbed. WHile you will get settling in the tracks, those tracks will be the low points, and you will have 2 little creeks on your driveway. If you want it to shed water, crown it! Also, if you have any clay in your road, you want to start with something much bigger, like 4 inch, especially if your contractor will be building this fall (rainy season) and driving anything like a tri-axle dump even once or twice. THese heavy trucks will really roll it in, and then you could spread the 2 inch crusher run and crown that.

Up here in the Northeast, we get some really soft ground in the spring after the winter thaw. We had a large addition built, and got a tri-axle dump stuck up to its axles /forums/images/graemlins/crazy.gif Had to tow it out with a track hoe /forums/images/graemlins/shocked.gif After that, the contractor said he needed to lay the 4 inch stuff (sometimes called cobble, or rip rap). This just lay on the road for the rest of the spring and summer. It was really bumpy, but I could crawl over it in a Saab 9000 without too much trouble. Now I have a really solid driveway taht only needs re-crowning every 4 years or so. That rip rap is now at least 8 inches down formthe top, just by churning and heavy traffic.

 

[Soundguy]

</font><font color="blue" class="small">( would strongly suggest that you DO crown the roadbed. .. If you want it to shed water, crown it )</font>

With respect... I do this for a living... a pile of gravel isn't going to shed water.. it is going to be a medium for the water to travel in ( the voids in the gravel ). The shape of the final non-porous road bed under the gravel will make more of a difference on the flow characteristics than the large consolodated 1/2" and 3/4" gravels. The exception will be gravel fines and 1/4 to 3/8 material, that when saturated, will flow differently due to less /smaller voids.

His gravel road will self crown quickly.. and yes, it will rut... he'll have to drag/blade that out anyway... no need to start with an existing crown, as it will still rut at the same rate.. except he'll have more drag/blading to do.

Soundguy

 

[stmiller2]

The Progressive Farmer web page has a snippet from an article that gives advice on roadway gravel size and depth.

 

[Kent]

Helpful road building links

I am sure I found all of these resources in this forum, but here they are together in one place:

USDA Manual
Army Field Manual
British Columbia guide
Backwoods Home article
Drainage Problems
Materials Calcuator

There are many product/implement-specific tip sheets as well, but they tend to favor one way of doing things, so I didn't include these. For example, installation sheets from conduit (e.g. Contech ) and geotextile vendors, or instruction sheets from implement mfgrs (e.g. Terrabond ). I remember a really informative tutorial from a heavy-duty truck-mounted landscape rake mfgr, but I can't seem to find it right now (I noticed last year a gravel road crew in NH using this implement with great success churning up 4" of gravel, but my 3-pt hitch rake is only heavy enough for a light smoothing).

 

[gerard]

I'm with soundguy - If you're putting down clean gravel I wouldn't worry about crowning for his stated reasons. Once you top with running crush that has some fines, then worry about crowning since then, even while still somewhat porous to water, in a medium to hard rain, the surface won't absorb the water as fast as it's coming down and you'll have surface runnoff. That's when you'll want the crown to prevent the water running lengthwise down the roadbed in the tire rutts. Kind of pricy for a 1000 foot road but if you REALLY want to do it right lay down some geotextile fabric FIRST, then put your base on that. It'll prevent your base from migrating down over time. (15 foot x 300' roll is about $150 if memory serves.)

 

[John_Mc]

</font><font color="blue" class="small">( That would be great on a hard surface road that is shedding water.. gravel is so porous that water will be traveling beneath the substraight... it will be like an aquifer... I'd go flat.. besides.. it'l crown on its own with traffic.. and he'll have to blade that out as well.)</font>

Actually, JMIII's formula (1/2" per foot) is standard operating procedure around here. In addition to reducing erosion from running water, it helps prevent standing water on the roadbed. Standing water is a road killer, since the puddle area softens up over time and turns into a pothole. That becomes a vicious circle, since the pothole now holds more water, which softens up a larger and deeper area. Maybe this doesn't happen in Florida, with the type of dirt/gravel you have down there, but it's a major concern up here.

John Mc

 

[gsganzer]

That's the scenario I've found on my driveway. The last time I graded, I crowned and sloped to prevent standing water. Like you said, a puddle leads to a self-perpetuating downward spiral.

 

[Soundguy]

I think you are missing the point I am making. I didn't argue against the 1/2" per foot.. etc.. I said that on a roadbed made of large gravels.. it wouldnt make a difference. If he has a surface course of gravel fines, silt, clay, or limerock that will hold/shed water.. then yes.. crown it by all means. If he has a 3-6" deep gravel like 57 stone... water is not going to puddle on top of it.. it will run thru it like a seive.

I'm familiar with potholes.. florida is virtually all carst topography due to our aquifer.. besides.. I've already had pothole 101 in college ( civil eng. )

Soundguy

 

[oldmisterbill]

This is an interesting topic - I have been dealing with Oklahomas torrential rain latley. (origionally from Pepperell Massachusetts) Which I am not used to.I did custom tractor work in MA. I never had a box blade but used a scraper blade & a york rake (stone rake is what it is called in this area) the thing that amazes me is there are very few rakes in this area and most seem to rely on a box blade only. In my opinion I would atke a rake over a box blade if I had a choice of only one tool. Why? because after it is roughed out with a box blade a rake will finish it almost perfectly, When it needs repair or refinishing,a rake will move only enough material to level and fill the holes or ruts. This in my opinion leaves the hard packed material untouched still packed and only the small amount moved needs to repack. I did a lot of this in MA ,and felt I was doing people a favor. Then when I moved down here 13 years ago I was surprised to see box blades every where. I used one for the first time last year -it was great,but I spread two truckloads over a washed out drive and still liked the rake better for a better surface and grade. I used the box for some narrow excaviting & spreading next to a foundation and loved it.

I think this is a good subject for disucssion and to be critizied as a means of improving our skills.