gravel road and parking lot in Montana
gravel road and parking lot in Montana
(OP)
I am trying to build a gravel road and gravel parking lot in Montana in the least expensive way. The soil is a hard clay. Does anyone have any suggestions on the design and type of gravel, etc?
Thanks
John
Thanks
John





RE: gravel road and parking lot in Montana
KRS Services
www.krs-services.com
RE: gravel road and parking lot in Montana
Thanks
John
RE: gravel road and parking lot in Montana
The geotextile will separate the gravel from the soil - provided that it is not a woven product on clay or silt soils. It will also provide some tensile reinforcement where it is needed most.
But the absence of anything to "hold" the gravel together concerns me. Four to six inches of road mix gravel could easily be three inches in some areas. That's not enough cover to either protect the geotextile or provide a pavement "structure" where the geotextile and gravel work together. This concern is really a maintenance issue; maintain the drive and you shouldn't have too many problems.
RE: gravel road and parking lot in Montana
KRS Services
www.krs-services.com
RE: gravel road and parking lot in Montana
RE: gravel road and parking lot in Montana
What did you decide to do? I'm just curious.
KRS Services
www.krs-services.com
RE: gravel road and parking lot in Montana
I agree with Focht3 and SirAl. My experience is that geotextile fabric is used to bridge soft areas of your parking lot, but in order to do this, you need more than 50mm of fill. I've used Mirafi in the same situation, for which at least 18" of fill is recommended for proper stabilization. The reasoning has been to me as a 'trampoline' effect; the fill surrounding the soft area will hold the fabric taught, minimizing movement of the ashpalt on top of it. But you need enough fill to 'pin' that fabric at the edges, giving it the holding power to bridge the soft area.
I would get a loaded gravel or water truck and roll it across your clay. If you were able to get a look at it last winter/spring during the rainy season, I'd use that information as well. If that clay base moves enough to worry you, I would overexcavate 18", lay down the fabric, followed by 18" of fill, your crushed layer, then pave. If you do a proof roll feel that all of that work would just be rediculous, I would just pave as-is, with the 2" lift of crushed rock, with maybe and inch or so more asphalt just to be sure.
Best of luck! Let us know how it went.
RE: gravel road and parking lot in Montana
I would use a geotextile of the geogrid type (as Focht3 states a woven product is not required here) If the clay is a hard clay a geogrid membrane will separate the materials and reduce the thickness of fill required.
Next I would place a 3" clean crushed limestone layer, as thick as the construction budget will allow. Best if this is 12" thick and as single sized as possible,if not as thick as can be afforded. After this continue to compact with a vibratory roller and spread crushed rock fines. On top your gravel surfacing couple of inches thick.
Of course drainage is the key and falls should be to open ditches which are well maintained.
Zambo