concrete volumn

[Ranieri]

If memory serves, a 60 lb sack of Quikrete yields about 1/3 cu.ft.

[Sam the Cat]

Folks, I am looking for the volume of concrete in a 60 and 80 lb bag. It seems its only sold by weight and the quantity calculators online at either sakrete or quikrete are PIA since you have to convert to "equivalent slab" size. Someone has got to know the numbers -- looking for something like x cuft / 60 lb bag etc

TIA

[Sam the Cat]

Doug

Thanks !

[RicodJour]

Let's see, you did one little form, and Bob did 600 much larger placements. So your one test outweighs his 600? Yeah, right.

The manufacturers' literature (all of them) indicate .6 CF.

They also state to add 6-9 pints (2.8-4.3 liters) of water. 1 liter =

2.2 pounds, use the high number > weight of water = 4.3 x 2.2 = ~9.5 pounds

Your version has concrete weighing 90 pounds (80 pound bag, plus ten pounds of water - and some of that water evaporates). That's some damn light concrete! Real world concrete, as opposed to imaginary, weighs in at ~150 PCF. Even lightweight concrete using flyash and other much-lighter-than-usual aggregate weighs in over 100 PCF.

Let's check Bob's version:

2 bags @ 80# = 160# 2 x 4.3L water = 19# totals to 180# manufacturer's lit, .6 CF/bag x 2 = 1.2 CF 180#/1.2 CF = 150#/CF

His numbers check, yours don't. Do the math.

R

[Doug Miller]

Look at the spec data sheet

YIELD ? An 80 lb (36.3 kg) bag yields approximately 0.60 cu ft (17 L) ? A 60 lb (27.2 kg) bag yields approximately 0.45 cu ft (12.7 L) ? A 40 lb (18.1 kg) bag yields approximately 0.30 cu ft (8.5 L)

[barbarow]

[User Example]

I have an 80lb bag of premix concrete in my garage that says 1 cu. ft. on it. And based on use, I'd say it is right.

[Robert Allison]

And you would be wrong. I have done about 600 replacements of balcony decks on apartment complexes (2" of concrete on a wooden substrate, each about 6'x8'). The first ones that we did, I measured the cubic feet needed for the deck and bought the appropriate amount of bags (marked 1 cubic foot). On the first one we were 12 bags short. I recalculated and it came out the same.

I returned to my concrete supplier (instead of home depot) and bought identical weight bags of concrete (80 pound bags). These, however, were marked .60 cubic feet. I did the calculations again. The next deck had 1/2 bag leftover.

Now I use the .60 measurement and it comes out pretty close every time, even when I buy the stuff at home depot that is marked 1 cubic foot.

[User Example]

No. I would be right. I made a 35" x 16" x 6" form and it took less than two bags. Do the math. Not sure what you are using but you don't get as much per bag.

Gary

[Rudy]

Those 'cheapie' (60lb ?) $ 1.39bags at HD say 1/2 cu ft on them.

[RicodJour]

Interesting, that. Being called a fool by a fool.

You have a very strange position on this. How can both be right? 0.6 CF = 1.0 CF. Does that look right to you? If it does, you shouldn't be telling people to do the math as you're more than a little shaky on it yourself. If the bag is marked incorrectly, that's not your fault. If you miraculously got that 80 pound bag to expand by 40% in volume, you should start a church.

I have no idea why they would print such a large volume number on the bag. It's not like the manufacturer would make more money/sales by doing that. The volume is what it is - you need the correct number of bags regardless of how the package is marked.

Either the weight as marked is wrong, or the volume is wrong. Since you'd probably have noticed if the bag weighed around 130 pounds, it's probably the marked volume that is wrong. Either way, it's wrong and that's all that matters. Someone should contact a lawyer and start a class action lawsuit.

R

[Robert Allison]

Exactly.

I hate bags of concrete. I love trucks full of concrete with a pump truck.

We just poured a new slab today with a 36 meter pump truck and

16 trucks of concrete. Easier than one of those damn 6 x 8 decks. At one point we were doing 12 of those decks per day. That took pallets and pallets of concrete mix, 4 halfyard mixers, and a crew of 24. We placed that 128 yards of concrete with 8 guys (not counting the truck drivers or pump operators).

[User Example]

Hey smart math boy. Why don't you take yourself down to the local Home Depot and look on the blue 80lb bags of concrete and then tell me what it says. If it doesn't say 1 cu. ft. then come on back here and tell me about it. Otherwise, why don't you shut up? I've got the bag right out in the garage and I can read what it says. And I poured it and I know how much space it filled. I don't care who Bob is or what he is pouring but unless he is using the same bags I did then you can't say he is right and I am wrong. Maybe we are both right. Either way, you are a fool for thinking you know it all.

[User Example]

Go to HD and look at the blue 80 lbs bags then report back to me.

[gfretwell]

[User Example]

Obviously you guys are complete morons and there is no arguing with you. I tell you what the bag says and I just filled a hole with it 2 days ago so I know exactly much one bag is yet you people will try to convince me otherwise without even looking into what I am saying. No wonder there are so many idiots out there that can't do anything without hiring it out.

[RicodJour]

A) Learn to quote correctly when you post. B) You're not arguing with me. You're arguing against physics. Unless you've found a loophole in the conservation of mass, you lose. If you did find a loophole, contact the Nobel Prize board immediately - they'll probably bump you to the head of the line. C) You either can't measure or are lacking basic math skills D)

Now please, STFU.

R

[RicodJour]

Bob, who's the manufacturer? I want to call them up and give them hell. Kind of a hobby. ;)

R

[gfretwell]

You must have bought the magic concrete. Bonsal says 80lb is .6cu/ft but what the f*ck do they know they just made it.

[gfretwell]

What brand is that? I buy a lot of bag mix from HD (Bonsal/Sakrete) or Lowes (Quikrete) and they always say .6 cu/ft for 80 lb. I have seen some 60s that say .5 cu/ft at Lowes but the HD ones say ..45.