1/4" River Sand 4

[dik]

Does anyone have a gradation/spec for 1/4" River Sand? I assume that the material should be rounded aggregate and not washed to remove the fines.

The material is used for bedding electrical conductors to provide thermal conductivity with no sharp edges to damage the conductors.

Dik

 

[cvg]

just specify pea gravel, most contractors are familiar with it

 

[dik]

Thanks... but, pea gravel doesn't have enought fines... there has to be good contact with the electrical conductor.

Dik

 

[dik]

First kick at the cat...


1/4" 'RIVER SAND'
ROUNDED MATERIAL, CONSISTING OF HARD DURABLE PARTICLES FREE OF CLAY AND SILT LUMPS, CEMENTATION, SOLUBLE MATERIALS, ORGANIC
MATERIAL, FRIABLE MATERIAL, FROZEN MATERIAL AND OTHER DELETERIOUS MATERIALS

FILL SHALL CONFORM TO:
SIEVE SIZE (ASTM) PERCENT PASSING
1/4 INCH 100
NO.10 80-95
NO.20 75-90
NO.40 50-85
NO.80 20-60
NO.100 05-30
NO.200 0-10

Anything look 'out of whack'?

Dik

 

[cvg]

good luck trying to find that - guaranteed with that tight of a spec that nobody can produce it without setting up a special screening operation at a huge cost.

Either a)call the local materials suppliers and see what they have that might work or b)give a sufficiently loose spec such as:

100% passing 1/4, 20% passing #100 and should be "well graded"

 

[emmgjld]

I would remove the well graded requirement.
Typical for my area, Upper Colorado River, to insure enough fines.

#4 70%-100%
#10 60%-80%
#40 25%-40%
#100 8%-20%

 

[cvg]

emmgjld your gradation matches my spec, and appears to be well graded... well, if you want higher inplace density and less voids, then go with the well graded spec. If you want more voids, more permeability etc, than allow gap graded or uniform material

 

[BigH]

What does natural river sand in your area grade out as? The Fraser River river sand was excellent - very free draining. See what is locally avaiable, then check out its gradation, then make the call. You wouldn't want to manufacture something if it wasn't necessary.

 

[dik]

Thanks, gentlemen... will modify and make it less restrictive... it's not free draining that I require, but a 'bedding sand' for conductors that will readily dissipate heat.

Dik

 

[Ron]

Dik...you might consider specifying a mix of 50 percent No. 9 stone and 50 percent Ottawa sand. You probably won't get Ottawa sand (from Ottawa, Illinois), but it has a somewhat "standard" gradation that many sands come close to meeting, and it's rather well known

 

[dik]

Thanks, Ron, the Ottawa sand that I'm familiar with is for densities of granular material... I'm looking for something that has a lot of fines to minimise air voids. I think the last 'simplified' gradation will do the trick... we've forwarded this gradation to the pit to see if it is something that can be obtained by removing everything greater than 1/4". The electrical code used requires the max size of sand particle is 1/4".

Dik

 

[dgillette]

Would ASTM C33 concrete sand work for you? Readily available. Some sources may have a better gradation for your purpose within this range.

3/8" - 100% passing
#4 - 95-100
#8 - 80-100
#16 - 50-85
#30 - 25-60
#50 - 10-30
#100 - 2-10

DRG

 

[dik]

Thanks, it has a gradation that is recognised. I'll pass this on, too. The 3/8 would have to be removed since the electrical code, I understand, does not permit material over 1/4".

Dik

 

[dik]

Forgot to add, the aggregate must be rounded material.

Dik