Cubic Yards to Square Yards
by patriot05 on 08/22/05 at 13:28:03

I need to place 2000 SY of 18 -24" crushed concrete (rip-rap).  I pay a certain price per truck load which is in CY (approx 13 - 15 per truckload.)  How many truck loads will I need?

Re: Cubic Yards to Square Yards
by Robert Fogt on 08/22/05 at 22:03:10

The formula for volume is:
Volume = Area * Height

They just all need to be the same base unit, such as yards.

You know the area, 2000 square yards, so you just need to know how thick you want to lay it, in yards.

For example, if you want the rock layed 1 foot thick, you convert 1 foot to yards then multiply:

2000 square yards * (1/3) yards = 666.67 cubic yards

666.67 cubic yards / 13 cubic yards/truck = 51.3 trucks
666.67 cubic yards / 15 cubic yards/truck = 44.4 trucks

So you would need between 45 and 52 truck loads if you wanted the rock 1 foot thick.  Replace the actual thickness in the formula above.

Re: Cubic Yards to Square Yards
by patriot05 on 09/14/05 at 17:32:36

If I buy the rip-rap in tons, how many tons will it take to get to 2400 sq yds.  I think I need to know the specific gravity of concrete?
Help?????

Re: Cubic Yards to Square Yards
by Robert Fogt on 09/15/05 at 01:01:38

Yes, you would need to know the density.

I searched but could not find anything specific to crushed concrete.

I have data on concrete gravel, and crushed stone, but I couldn't say how accurate those values would be for your product.

Re: Cubic Yards to Square Yards
by patriot05 on 09/15/05 at 08:35:41

Thanks for your help.  Concrete gravel seems like it would be a better match for density than crushed stone, what do you think?  The density of concrete is 2300kg/m3.  (I got that off the web.)  I used that as a starting point to determine how much to order.  What is the density of concrete gravel and just as a comparison, crushed stone?

Rip Rap is bigger than either of those.  The chunks of concrete are about 18" to 24".  The shapes vary so it's difficult to determine volume but I used both 6" and 12" converted to cubic meters and then multiplied by the density of concrete to arrive at kg.  I then converted that to short tons.  If I also calculate using the density of concrete gravel and crushed stone, I'll have a better estimate.

Re: Cubic Yards to Square Yards
by Robert Fogt on 09/15/05 at 19:19:22

Crushed stone has a density of 1600 kg/m³ and concrete gravel has a density of 2400 kg/m³

Your density data is probably for concrete asphalt, which I show has a density of 2240 kg/m³. There is also Portland limestone concrete with a density of 2370 kg/m³

Anyhow, your rip rap will probably be less than the density of solid concrete because of gaps between the pieces, the bigger the pieces the bigger the gaps.   I would guess it is somewhere between 1600 and 2000 kg/m³.

You could calculate for both values and give yourself a minimum and maximum estimate.

Re: Cubic Yards to Square Yards
by patriot05 on 09/16/05 at 08:39:32

Thanks so much for your help!

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