2 year grader operator here and I'm looking for some insight on gravel shaping. I'm using a 770D with 12' blade. I have been final shaping gravel roads for cover seal work. The majority of them have brown gravel as their base. Brown gravel in my area has alot of big aggregate unlike white gravel CA-6. The question I have is, what's the best way to push that bigger aggregate to the bottom so you are left with a nice smooth surface? Let me explain on how I deal with a 16' roadway with no potholes. After my water truck has sprayed down and back, I'll cut both ways bringing my material to center. I'm keeping a light toe, so not leaving a ridge on shoulder, and cutting 'bout 2 inches in depth with my heel, usually zero's everything out. Then I have my water truck spray my winrow and the lane that he is in, he will stay on the right side of the winrow. I am right behind him, but I am kicking my material to the right a few feet off of center. We both get turned around and do the samething coming back, but this time I'll kick my material to center. I am not cutting anything while doing this, just running a light blade mixing moisture into my winrow. I then flatten my winrow out to zero, leaving my gravel just a bit wider than my machine, and not having gravel spill out around my blade. We use endplates on our moldboards, so at this time I would slap my right side end plate on and start putting crown into road. Carrying material in my endplate that I have pulled from the center, but not cutting the center of the road at all, very light toe. I put crown into the whole roadway, 'bout 3/16 in a foot. Then I have my water truck water again and have our roller roll the roadway dry. Am I not cutting deep enough to hide the big rock? If so, how deep should you cut the roadway? Not enough water before the roller gets on it? Should I cut the road twice, meaning, cut deeper first time and lay the road out. Then cut again, but not as deep so the big rock stays down. Any ideas or tricks of the trade would be great. -shiggy
misspelled a word, winrow = windrow, my bad plz excuse it -shiggy
In order to hide the big rock you need to have lots of material to work with. If you don't have enough material especially using end plates the rocks will just drag along. When I shape up a road I work the material back and forth, build my crown and weed out and bury as many of the rocks as I can. Once the road gets packed down (a few days) I will come back and make a light cut and get rid of any excess rocks. Remember I work with no water truck or roller. I think if you work with more material and with having a roller you should be okay.
In parking lots and subdivision roads.I sludge my base in..Get it wet,real wet, mix it so you get the material to a point where your gradation will make a good hard surface when it cures.I lay that wet base up to my curbs slightly high.Roll it with a vibratory smooth drum. You`ll know its right when its doughy rolls up your mouldbourd rather than drift out the side like a dry material and it is pumping from wheeled vehicle traffic.I put it in at way over optimum moisture.This will help you as well when you test it for moisture and density.As the water comes out of it,the density will go up. Let it cure a day or two if its not hot outside.Usually a day or so here in my climate and my base is rock hard. Then I blue top it,(usually easier to do while base is still green). A common mistake I see in young operators is rolling their mouldboard to far forward where they tear their base rather than cut it. I use light shots of water as I get closer to my finish product. I burn finish with my mould board rolled all the way back to get that slick finish. If you are having trouble with excessive amounts of rock ,mix your base much wetter. I will process base all the way back down to subgrade and lay it back in. If you are getting rock pockets on your edges,you need to mix with more water. In the summer here I will get it so wet the water truck barely gets through it.. be patient after this,let it cure so all you are doing is cutting not filling with dry material. A water truck is your best friend,use it a lot. Gene
thanks a bunch for the replies here's what I am thinking 'bout trying, having my water truck spray my windrow for one more round and mixing that up. Plus I will cut my base a little bit deeper. I'll see how that goes. Just trying to figure out how to bring fines (the cream) up to the top for that ultra smooth finish. Probably won't get that smooth finish that I am after due to the fact that we use rubber tire rollers. I think there is a little fine line there between optium moisture and too much water, am I right to say that? Seems to me that I get a bit nevrous when I tell my water truck to shoot it again. That might be my prob, not wet enuff. BTW, when doing gravel i usually roll my moldboard forward so the top is 'bout an inch or two farther forward than the bottom, gives it that oso nice mixing action. Next time I shape, I'll try a few different things and post back. thanks again -shiggy
To get the fines up..Get it hard first then water the top heavy and wheel roll it before you do anything.Lots of water on top and a wheel rolling will give you that cream on top. Good luck to ya, Gene
Try to bang 'em down or break 'em up with the roller. This helps but doesn't get rid of them all. I'll usually wind row whatever I can't get out and have a loader pick 'em up.