cubic feet

I`m planning on doing a small concrete job. It will be 3 12 in. wide by 42 in.long by 4 in. thick slabs. I would like to know how many cubic feet are in 1 80 lb. sack of ready mix. Thanx a lot
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On Jun 16, 6:38 am, snipped-for-privacy@webtv.net (Herb and Eneva) wrote:

According to this calculator http://www.quickrete.com/Calculator/Main.asp#concrete , you would need at least 6 bags for the whole job. An 80 lb bag yields . 6 cubic feet.
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That's .6 cu ft. Forgot the decimal point.
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I would agree with Mike's number of .6 cu ft for an 80 lb bag
I use .44 cu ft for a 60 pound bag of "bagged concrete mix" so that would give Mike's 80 lb bag .587 cu ft.....close enough :)
So how where does the rest of the weight per yard come from?

Dan's number of .5 cu ft per 80 bag underestimates the concrete yield "slightly" but in small batches; waste, form volume underestimation & form "leakage" can easily eat up that margin.
Cheers Bob
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I actually got this info here on quickrete spec sheet
http://www.quickrete.com/PDFs/SPEC_DATA-ConcreteMix.pdf
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1 cubic foot of hardened concrete weighs 150 - 155 pounds.
I NEVER count an 80# sack of premix for more than a 1/2 cubic foot. I've not ever had extras.
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