Washboarding on gravel drive

[yanmars]

Just recently my gravel drive got a great deal of washboarding. No different equipment up and down the drive. Only real change over the last several months is extreme drought.
Any thoughts that caused this and the best way to remove?

 

[paulsharvey]

Just recently my gravel drive got a great deal of washboarding. No different equipment up and down the drive. Only real change over the last several months is extreme drought.
Any thoughts that caused this and the best way to remove?

You kinda already know the reason, it's dry. You have to have something cohesive to prevent wash boarding. Depedning on the driving surface (sand, dirt, clay, base rock, gravel), you May be able to add something that will bind it together better, but in the end, moisture is needed for almost anything to bind together. To help avoid making it worse, drive slow, in different tracks, will help.

To temporarily remove, they can be graded out; BUT, grading will loosen and remove more moisture, making it come back soon, and worse

 

[paulsharvey]

They do make spray on polymer binders, but I have no experience with them. Old timers will say spray with motor oil and diesel, but I wouldn't, not that I'm an environmental guy, but that's a step too far for me. Calcium Chloride based dust suppressants draw moisture from humidity to keepndust down, but I would think this would be worse than road sale for rust?

 

[paulsharvey]

Depending on your base driving surface, adding some clay into the material May help, with sand, or graded aggregate. If the base is a "road base, limerock, crusher run. millings, ect" type material, and depending on your budget ,and length of the drive, once it's regraded, and you get some moisture and compaction, you can look at having the driveway primed and sanded. It's not terrible expensive, IF, there is a contractor in the area. The next step up from that would be having it chip sealed.

 

[gengine]

Generally speed and traction are factors of creating the washboard. I don't know anything about your driveway, as far as length, grade, etc. Using a blade to "cut the highs and fill the lows" won't get rid of the underlying issue, the loose material you cut off the top will fill the lows, but won't stay there until it is locked in.. To solve it, you have to cut deep, almost to the base layer, wet it down, grade, and compact, so the full depth of your road base "locks" together. Figure out the cause first. Speed makes a traction issue where a wheel spins a little occasionally, making a divot and a hill. The more it is done, then you develop consecutive divots and hills when the wheel spins on the loose hills causing wheel spin, then the wheel digs into the packed divot piling up loose material behind it. Grade is the same way, the constant grab-spin-grab-spin of the wheel making the washboard. The biggest thing I have found beside speed and grade, is private driveways are built with "reject" road base, meaning the material doesn't meet county/state/federal spec for road construction for any number of reasons, mostly rock to dirt ratios, so they sell the reject material for private driveways. Too much 3/4" rock to fines, too much fine material to rock ratio, etc. There is a balance. Our reject road base here has a lot of sand. Ever try to compact sand? Doesn't work. To tell if it is good stuff without the fancy scientific tools, is to grab a good sample, not just the stuff on top, but get in there, rocks down to the fines, get it moist, (not sloppy saturated), make a ball out of it, and squeeze the heck out of a ball, like your making a snowball. Once you have a ball, press your thumb into it. If it immediately cracks and breaks apart, there is not enough binders (fine material) to glue it together, or there is not enough fractured rock to "lock" it together. Look at your sample. Too much rock from the bigger 3/4" on down, won't lock together. If the bigger rock is all round rock, there is nothing to lock it together. For example, rub two eggs together...the round surfaces don't "lock". Too much sand will have the same effect. Too much fine "dirt" and your sample will smear, meaning there is not enough rock to lock it together. Your sample should crack and smear at the same time, to have a good sample. As far as what you have already in place, consider having it mag sprayed. Your material may be less than par, but the mag spray will hold it together, plus keeps the weeds/dust down.

 

[gengine]

They do make spray on polymer binders, but I have no experience with them. Old timers will say spray with motor oil and diesel, but I wouldn't, not that I'm an environmental guy, but that's a step too far for me. Calcium Chloride based dust suppressants draw moisture from humidity to keepndust down, but I would think this would be worse than road sale for rust?

I replied mag spray, which is Magnesium Chloride. Calcium chloride will have the same result, very effective, but keep the vehicles clean (garden hose) with both for the first week + until it really soaks into the dirt. I don't know anything about Polymer binders to share any knowledge.

 

[bmaverick]

Just recently my gravel drive got a great deal of washboarding. No different equipment up and down the drive. Only real change over the last several months is extreme drought.
Any thoughts that caused this and the best way to remove?

Got a box blade with rippers? Or a ripper bar? Then come back over it after several ripper passes with a straight blade at an angle.

On the Kubota forum, this guy laid down iron grates and then filled the gravel over it.

More solutions are like this. Mainly a flexible chain-link fence on the ground. It follows curves and can track well down or up slopes.

If you can not afford the grids to lay under the gravel, others have added a layer of black cinders. Once you drive for a few months with the cinders, a resin can be added over the top. This will make the cinders tightly strong like a 2-inch layer of concrete.

Cinder pre-resin,

This is after the resin is applied.

 

[paulsharvey]

Gengine, is 100% right and describes it very well.

If you give us some pictures of what you are working with, we probably can get you pointed in the right direction.

Also, rough measurements would help, because what is a legit option for a 200 lf drive may not be for a 5000lf drive.

 

[yanmars]

Thanks for the replies. The lane is over 1500 feet, about 10 feet wide. Mostly there for 20 plus years. Took out all the top soil and probably 6 to 8 inches of 3/4 hard gravel. I do have a box blade with rippers and a heavy duty commercial chain type drag.
The drag is easy to use, the box blade is a bit of a pain to remove my heavy duty mower and then have to reattach it.
My cousin has a very good lane leveling tool. He used it once before with good results. I may have him do it again when we get some moisture. May just use the drag until then.

 

[paulsharvey]

Thanks for the replies. The lane is over 1500 feet, about 10 feet wide. Mostly there for 20 plus years. Took out all the top soil and probably 6 to 8 inches of 3/4 hard gravel. I do have a box blade with rippers and a heavy duty commercial chain type drag.
The drag is easy to use, the box blade is a bit of a pain to remove my heavy duty mower and then have to reattach it.
My cousin has a very good lane leveling tool. He used it once before with good results. I may have him do it again when we get some moisture. May just use the drag until then.

Don't go ripping it all up with zero moisture, you will make things worse. You probably need to get some fines into that 3/4" gravel. Washed rock really doesn't bond into a single cohesive base. This could be done by adding some screenings, sand clay, or "brick pavers base". Those would need need worked into the gravel, with moisture.

I have never priced the spray on gravel binders, but at 15,000 sq ft/1670 sq yards, I would think they would be cost prohibited

 

[paulsharvey]

I did just look at a product called Gravel Lok, it's about $100/gallon, and it covers about 80-100 sq ft per gallon. No way is that a real option. We would be at about $15,000. You could probably have the entire 1500 ft drive chip sealed for less than that, or atleast in the same ball park, for a proven, widely used, good product

 

[paulsharvey]

So, as an example, here is a North FLa based paving company/asphalt plant that Actually puts prices up. Now, as a background, Trackless Tack is more money than what I like, Special MS, a medium set, asphalt emulsion prime/tack. Track less has a wax additive to avoid tracking, so Special MS is actually cheaper, and can be diluted (Nebraska DOT did a study, showing that diluted prime, if applied with a heavier total Gal/SY did just as well, as less spread, higher concentration), would do a very good job of binding your gravel. The struggle is finding a company that does priming/tacking/chip seal. But $6/gal for a known product vs $100/gal for some magic in a bucket resin...

 

[paulsharvey]

You could probably do something like a 0.15 gal/sy application of asphalt emulsion over your gravel (once graded), and sand the top, and be pretty happy with the results.

This would Not restrict you being able to Pave or chip seal later if desired. Some of the polymer/resin products May. Oil or diesel sprayed would certainly.

 

[paulsharvey]

Here is a direct copy and paste of Clay County FLa Public Works statement on dirt roads.


Dirt Road Maintenance

Clay County has approximately 247 miles of County-owned or maintained dirt roads. More than 90% of these roads consist of sand and clay, which comprise the road base. The condition of these roads is highly dependent on the volume and type of traffic, drainage systems, and weather conditions. Erosion of unpaved roads and drainage systems is the most significant factor affecting maintenance requirements.

Erosion of unpaved roadways occurs when soil particles are loosened and carried away from the roadway base and into the drainage system. Soil particles that settle out in the drainage system reduce the ditch's carrying capacity, which in turn causes roadway flooding and, thus, more roadway erosion. Grading dirt roads with little moisture content in the soil is futile and is often the cause of road surface degradation, such as "washboarding" and other problems associated with soil loss. Frequent, excessive, and unnecessary disturbances by continued grading increase erosion, which accounts for a large percentage of dirt road maintenance costs and the deposit of sediments in our water bodies. Properly timed and selective surface maintenance, which includes drainage systems, will minimize erosion problems and lengthen the life of the road surface.

 

[paulsharvey]

The erosion part, they kinda give it an environmental spin, which it does cause turbity, i think they largely are basically talking about the loss of the clay binder, and the sand, which makes up the bulk of material. In part of the world that have gravel, I think the same largely applies.

 

[Rockbadchild]

Wash board is created by accelerating vehicle on surfaces that have poor traction, il will happen on hills and after corners every time on gravel road. Have you consider calcium treatment? or slowing down?

 

[yanmars]

On the lane itself I really do not have hills as such, slight inclines and I travel the lane under 10 mph, usually 5 mph or so. Perhaps that is too fast?

 

[Rockbadchild]

On the lane itself I really do not have hills as such, slight inclines and I travel the lane under 10 mph, usually 5 mph or so. Perhaps that is too fast?

Fast or maintaining speed is fine it's acceleration the problem... But in a way there will be no way around it, eventually it will happen. Also if there was washboard at one point and gravel was simply added on top, washboard or pot hole will mold that and resurface.

 

[pmsmechanic]

Fast or maintaining speed is fine it's acceleration the problem... But in a way there will be no way around it, eventually it will happen. Also if there was washboard at one point and gravel was simply added on top, washboard or pot hole will mold that and resurface.

Yes to the above and also if you want to completely get rid of washboard you need to loosen the gravel to the bottom of the washboard and grade it smooth. A bit of compaction at this point goes a long way. After a good rain is an optimal time for doing that. Then as you drive over the gravel it kind of locks into place. After that avoid the hard acceleration that contributes to washboard formation.

 

[gsganzer]

I think one of the biggest causes of washboarding is excessive speed. On my deerlease, when the old rancher was still alive and working, the ranch roads were always in pretty decent shape, with the exception of places where it would get washed out with rain.

After he passed, the son-in-law took over. The roads are all washboard now. The difference is the son-in-law drives crazy fast on the roads.