Square feet of rock/gravel

LAA · Mar 20, 2018

Rule of thumb we have long used is a ton of rock/gravel is 21.6 cubic feet, so 3 inches deep equals approximately 85 square feet. Using some railroad rock today and it's running around 120 square feet to the ton, it might settle but it's pretty good size material, anyone see similar before?

Mike(NEOhio) · Mar 20, 2018

All the railroad I've ever seen is slag. Much lighter than limestone. And larger sizes will take up more volume than an equal weight of finer size.

Steve in VA · Mar 20, 2018

The size of railroad stone is large enough that it is not packing as closely as smaller stone within the space. Generally, close packing of equal sized spheres in an infinite lattice is ~0.75 meaning that 0.25% is the free space between the spheres. Yes, the rock isn't really a sphere but close enough. So, if the railroad stone is being laid out at 3" depth, it's large enough to disrupt the packing and throw the generalization off. As the amount of free space increases then the stone will show more square footage per ton.

Of course I'm assuming that the railroad stone is roughly the same density as prior stone.

bjb in TX from Ne · Mar 20, 2018

2000lbs/21.6 cf = 95 lbs/cf

From my steel book:
Gravel 90-120 depending on size and moisture content
Slag 45-187 depending on type (iron slag is heavy)

ed will · Mar 20, 2018

When you use crushed rock and go by the ton it will go farther because of the voids between the rocks. We never go by the ton with base material here but rather by the cubic meter. We use "by the ton" only when figuring asphalt. For example: asphalt 85 sq ft to the ton for a 2 inch compacted lift. Ed Will Oliver BC

Trkr · Mar 20, 2018

On the subject,does anyone know how many tons of #57 stone I would need for a 24'x36' pad,2" deep? Thanks

JDPhil · Mar 20, 2018

I would get 15 or 16 ton should do it . I haul stone ever day so my guess!

Pete in MD · Mar 20, 2018

Your pad has a volume of 144 cubic feet. Using LAA's rule of 21.6 cubic feet per ton you need 6.66 tons. Call it 7 tons.

LAA · Mar 21, 2018

Thanks to all for the good information, I hoped the difference was due to rock size and that seems to be the consensus.

showcrop · Mar 21, 2018

I agree with Mike in Ohio. I am sure that it varies from place to place, but I have seen that it is often slag. Another major factor is that you, posted rock/gravel which tells me that it includes fines and small stones so it does pack densely, just the opposite of what most of the responses are telling you.

rustyfarmall · Mar 21, 2018

(quoted from post at 13:47:25 03/20/18) I would get 15 or 16 ton should do it . I haul stone ever day so my guess!

When I call the local trucker to bring rock for my driveway, he wants to know how much? I answer by asking, "how much can you get on one load"? I always have a place to put the excess.

fixerupper · Mar 21, 2018

(quoted from post at 05:32:24 03/21/18)

(quoted from post at 13:47:25 03/20/18) I would get 15 or 16 ton should do it . I haul stone ever day so my guess!

Click to expand...

When I call the local trucker to bring rock for my driveway, he wants to know how much? I answer by asking, "how much can you get on one load"? I always have a place to put the excess.

Same way here. I call for how many loads I think I will roughly need and make do with what I get. Got in two 23 ton loads of 2” limestone yesterday and spread it out as far as it would go.

Around here railroad stone is a red stone of some sort. I’ve never looked at it close but it definitely is stone.

Square feet of rock/gravel

LAA

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Mike(NEOhio)

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Steve in VA

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bjb in TX from Ne

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ed will

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Trkr

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JDPhil

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Pete in MD

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LAA

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showcrop

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rustyfarmall

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fixerupper

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