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by Allen

(Missouri)

Hello,

We are going to start mixing our own concrete for some projects around our farm. I found your recipes for mixing concrete on your website. I noticed your recipes go off of weight, which is great, but I was wondering the pounds per cubic feet of the aggregates you are basing your mixture off of.

I'm just trying to make sure we are going to get exactly 1 cubic yard out of the mixture since I'm sure densities of materials change quite a bit.

Thank you for your time and website. I find it to be very interesting and informative.

Thanks!!!

Answer:

In general, 1 yard of concrete weighs about 4050 pounds. 1 cubic yard of concrete equals 27 cubic feet.

4050 lbs divided by 27 cubic feet = 150 lbs. per cubic foot.

So 1 cubic yard of concrete weighs 150 pounds per cubic foot. If you break down the weight of the individual aggregates (cement, stone, and sand) in the concrete, you get the following weights:

517 pounds of cement /27 = 19 lbs per cubic foot

1560 pounds of sand /27 = 58 lbs per cubic foot

1600 pounds of stone /27 = 59 lbs per cubic foot

That equals 136 lbs per cubic foot for the dry aggregates. Above I said a cubic yard of concrete weighs 150 lbs per cubic foot, so the 14 lbs per cubic foot difference would be the water in the mix.

Keep in mind these "weights" are just a general description of a 3000 psi concrete mixture. Moisture content in the aggregates does play a part in figuring the overall weight also. But this should give you a basic idea of individual weight per cubic foot.