Sand as Pre Road Base

[JimMorrissey]

Anybody have any reason why/how compacted sand might cause problems as a pre-base material for a new road? I want the surface smooth and even before I put the fabric down. It makes for a nice surface for the fabric too. I can get the sand delivered for a pretty good deal ($120 per tandem / 16 yards). I also think the sand would be a good way to sculp the crown prior to the crushed gravel which is much more expensive. I'm also looking for it to be a fill material to bring the whole excavation up to the same grade.

 

[PineRidge]

Jim there is a lot of useful information here camp roads

 

[beenthere]

I think it would cause lots of problems.

 

[Toiyabe]

Should work fine. I'm not sure I know what you mean by "tandem", but you may not get 16 yards per load. If it's a standard three-axle dump truck, it will be overweight with 16 yards of sand. 10 yards is closer to reality.

You may have difficulty with compaction unless you hire a roller. If you can leave the sand exposed for a while and let vehicle traffic compact it, that will help. It will also help if you dump from the access road outwards to get the most compaction out of the delivery truck itself.

With a clean sand subbase you ought to be able to do away with the geotextile. The sand itself is pretty good at preventing the fines from the subgrade from pumping into the base.

 

[JimMorrissey]

Like what?

A friend of mine used sand a few years ago and it has worked great so far. The sides of my road are cut down into the soil so the sand doesn't have anywhere to squirt out to. I'll still use fabric to keep the road from compressing under heavy loads from cement trucks and delivery vehicles.

 

[Toiyabe]

Why are you excavating, rather than building on the surface?

Removing topsoil is good, but there's no reason to go any further unless you can get down to a good material. If you backfill into what is essentially a trench with impermeable materials on three sides you can be sure that the sand will stay wet year round. It would be best to provide some way for the sand to drain either by building above grade, cutting a ditch or installing perforated pipe.

 

[JimMorrissey]

I'm "excavating" in order to get down to something other than black topsoil! I'm not going to build a road on topsoil, and there's lots of topsoil; over 20 inches in places. It's impossible to get a perfected excavated surface with a backhoe, so I'm looking to even the surface out with the sand. As far as moisture goes, I have no doubt the sand will be moist most of the year. It won't be "wet" due to the fact that it will have heavily compacted crushed limestone with a 4" layer of compacted crushed stone on top of it. Rain will eventually run off this surface like asphalt. If it does get wet from below the water will be able to permeate the subsoil where it came from. Not sure why moist sand is an issue.

 

[rswyan]

In hindsight, one thing I wish I had done was spread some sand, or crusher run for that matter, on top of the geo-textile before I had put down the No.2 gravel. Some of the No. 2 had some pretty sharp edges .... using a layer with alot of fines first might avoid any issues with the sharp edges chewing up the geo-tex.

 

[Toiyabe]

Wet sand is certainly better then wet topsoil. Not as good as dry sand. Providing a way for the sand to drain will give you more structure, but it sounds like you'll have plenty.

 

[JimMorrissey]

Yeah, I agree. I intend to sandwich the geo in sand. I think you'll be fine though. The woven fabric is incredibly strong.