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Grading technique?

Discussion in 'Heavy Equipment' started by jomofo, Mar 13, 2009.

  1. jomofo

    jomofo Senior Member
    Messages: 272

    Howdy guys... got a question for those of you with some grading experience... Here's the quick backstory:

    The road I live on is about 4 miles from the access point to the pass. The first 2 miles are county maintained and the second 2 miles are privately maintained. Generally, we do a major road project once per year on the private half, which involves a full grading of the road. The public half is graded as needed, since it gets a good deal of traffic that we never see at the top of the hill.

    I'm not sure how the guy we hire goes about doing what he does, as I'm never there, but I do knoe he does a great job. Not only is the road in good shape when he's done, but it stays in good shape for a period of time afterward usually measured in months.

    I also do not know how they go about maintaining the public half, but I do know that on two occasions, the guy who did it has done it in such a way that the raod is in pretty good shape when he's done, but the washboard comes back very quickly - this last time in less than a week, if you can believe that sh!t.

    I'm just wondering what the difference is... Any ideas? Thanks guys!
  2. CityGuy

    CityGuy PlowSite Fanatic
    Messages: 17,220

    First off i asume he is using a blade (road grader). There are a lot of factors that come into play here:
    1. Depth the blade goes
    2. Packing ( what type and how heavy the pacher is)
    3. Amount of moisture in the gravel (I assume it's class 5 red rock or class 5 recycle)
    4. Wind direction and speed
    5. Weather Rain how hard it rains and run off.
    6. Number and types of vehicals traveling the road. ( Heavier trucks will cause the road to washboard faster). Also the speed of vehicels.
    7. Time of year. With the thaw in the spring the upper layers of the road will thaw during the day and then refreeze at night.
    These are just some of the factors that can come into play.

    DGODGR Senior Member
    from s/w co
    Messages: 641

    Hamelfire, in my opinion, is on the mark with his post. I would however like to add that grade will also factor in to the length of time a gravel road will hold up to use. The steeper the road is the quicker the washboards will return. I would also like to further explain Hamelfires' comments. If the washboards are not fully removed (cut all the way to the bottom of the depressions) you will probably not get good compaction in the depressions. If you do not moisture treat the gravel (or if it does not have moisture already) it does not matter how much compaction effort you apply...the material will not consolidate as it should. The formation of "washboards" is usually the result of tire slippage either while braking or accelerating. You will usually find this condition coming in and out of turns, at intersections and on hills. These are obviously places that vehicles will tend to be on the gas or brakes. Once a tire slips it will move some of the road material into a little pile (if you will). This pile now creates an irregularity in the road and this will allow the next tire (that comes in contact with it) to slip that much easier. Once the "pile" has become large enough the subsequent vehicles suspension will tend to bounce after impacting the pile. This bounce will slightly un weight that tire and allow it to spin thus the next "pile" begins to form. As the cycle continues the washboard section gets longer and rougher. If the gravel is not consolidated or bound together properly it will tend to move around easier under the forces applied to it by vehicle traffic. Moisture and compaction effort essential to proper road grading. Most likely whomever maintains the public road section does not add moisture and therefore the garvel is dry. The road will look nice and smooth when they are done but it will not hold up to use.
  4. jomofo

    jomofo Senior Member
    Messages: 272

    Thanks guys! That's exactly what I wanted to know.

    The guys here did give it some moisture, but 10 days later it's actually worse than it was in some places. the town even sent some other dude back up to hit some of it and there's another section I'm betting they'll do also. I wish to hell someone up here would go in with me on some equipment.
  5. sp6x6

    sp6x6 Member
    Messages: 58

    We have same problem here in MT lots of miles of gravel road, and it is costly to haul and dress road. On one of our roads they used some kind of expensive machine that actually ground up the larger rocks as it went