 science question
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Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
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I'm building a weight from concrete. The prepackaged, 60 lb. in a bag type. Although it's listed as 60lb.s, I'm wondering what it weighs after you add water to turn it into hard concrete. Obviously, after you add water, some of the water evaporates to leave hardened concrete. But does all the water evaporate, contributing no mass? Or is some chemically bonded to the crete, adding weight? Although I've worked with concrete for years, never had to consider the weight of it, to any degree. Answers? (As a factoid, there is about one gallon of water added to each 60 lb. bag mix, and water weighs about 8 lbs. a gallon)
Fidelis et Fortis
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Re: science question
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Joined: Jan 2005
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Monkey Butt
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Monkey Butt
Joined: Jan 2005
Posts: 7,630 Likes: 7 |
Weigh it before and after and let us know 
We all like to think of ourselves as rugged individualists. But when push comes to shove most of us are sheep who do what we are told. Worst of all, a lot of us become unpaid agents of whoever is controlling the agenda by enforcing the current dogma on the few rugged individualists who actually exist.
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Re: science question
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Joined: Apr 2008
Posts: 819
3/4 Throttle
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3/4 Throttle
Joined: Apr 2008
Posts: 819 |
It should weigh a little less than the combination of the concrete mix and the total water combined. Some water will evaporate, but the rest will bond with the silicates, tricalcium aluminate and tetracalcium aluminoferrite and that will make it strong and solid. 
I would be unstoppable if not for law enforcement and physics.
2002, Cardinal Red & Silver
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Re: science question
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Joined: Aug 2005
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3/4 Throttle
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3/4 Throttle
Joined: Aug 2005
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Good question.. and the answer is 'it depends'  Has a lot to do with the mix, amount of sand, aggregate, etc.. For a general rule of thumb, 1 cubic foot of concrete will weigh about 150 pounds. According to the specs, a standard 60 pound bag of Quikrete like that sold at the borg will make .45 cubic feet. If those numbers are correct, then 1 bag will end up weighing about 67.5 pounds more or less. Cheers, Brad
To be old and wise, you must first be young and stupid.
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Re: science question
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Joined: Mar 2009
Posts: 12,964
Stickman Yogi
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Stickman Yogi
Joined: Mar 2009
Posts: 12,964 |
Quote:
It should weigh a little less than the combination of the concrete mix and the total water combined. Some water will evaporate, but the rest will bond with the silicates, tricalcium aluminate and tetracalcium aluminoferrite and that will make it strong and solid.
Okay, I think we have someone here who knows a bit out these sort of things. Of course I was about to say the same thing (not) but ya beat me too it!  Just curious, Cyn... where or how did you come by this knowledge?
Live to love, love to live.
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Re: science question
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Joined: Jan 2005
Posts: 11,126 Likes: 13
Should be Riding
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Should be Riding
Joined: Jan 2005
Posts: 11,126 Likes: 13 |
for gosh sakes, just don't use this concrete weight as a counter -weight in your elevator. 
Blowing gravel off rural roads
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Re: science question
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Joined: Aug 2007
Posts: 10,730 Likes: 5
Should be Riding
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Should be Riding
Joined: Aug 2007
Posts: 10,730 Likes: 5 |
Quote:
for gosh sakes, just don't use this concrete weight as a counter-weight in your elevator.
that's all I was thinking too!
Always remember to be yourself. Unless you suck. Then pretend to be someone else.
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Re: science question
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Joined: Jul 2007
Posts: 6,060 Likes: 6
Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
Posts: 6,060 Likes: 6 |
Quote:
Quote:
for gosh sakes, just don't use this concrete weight as a counter-weight in your elevator.
that's all I was thinking too!
Toooooooooo laaaaaate!!! 
Fidelis et Fortis
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Re: science question
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Joined: Jul 2007
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Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
Posts: 6,060 Likes: 6 |
The more I thought about it, the more I was intrigued by the possibility of water being trapped and kept in the concrete. Forever? If you sqeezed concrete hard enough, would some amount of water be extracted? Does my 60 lb. coarse mix now weigh 68 or so pounds? (Chill out fella's, the concrete is encapsulated in a wooden frame.)(Saw this done in a catapult once, it held up just fine).
Fidelis et Fortis
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Re: science question
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Joined: Apr 2008
Posts: 3,937
Loquacious
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Loquacious
Joined: Apr 2008
Posts: 3,937 |
Quote:
Good question.. and the answer is 'it depends'
Has a lot to do with the mix, amount of sand, aggregate, etc.. For a general rule of thumb, 1 cubic foot of concrete will weigh about 150 pounds. According to the specs, a standard 60 pound bag of Quikrete like that sold at the borg will make .45 cubic feet. If those numbers are correct, then 1 bag will end up weighing about 67.5 pounds more or less.
Cheers,
Brad
Use 144 lb per cu .ft. for cured 2,500 PSI conc.mix with aggregate. 
And you may see me tonight
With an illegal smile
J. Prine
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Re: science question
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Joined: Mar 2009
Posts: 12,964
Stickman Yogi
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Stickman Yogi
Joined: Mar 2009
Posts: 12,964 |
This is of interest to me too, Rich because of the three stories my house is made up of. I live of the top floor which is ground level... the bottom two are built into the side of the mountain I live on. Now, it's only a matter of time and I won't able (or wanting) to use the stairs so an elevator (glorified dumb waiter) will be in order if I stay in this house.
Do you have plans drawn up that you can post so I can have a looky-see at what you are doing?
Live to love, love to live.
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Re: science question
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Joined: Apr 2008
Posts: 819
3/4 Throttle
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3/4 Throttle
Joined: Apr 2008
Posts: 819 |
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Okay, I think we have someone here who knows a bit out these sort of things. Of course I was about to say the same thing (not) but ya beat me too it! Just curious, Cyn... where or how did you come by this knowledge?
I love chemistry and science, just too ADD to apply it to my life in any appreciable way!
I would be unstoppable if not for law enforcement and physics.
2002, Cardinal Red & Silver
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Re: science question
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Joined: May 2008
Posts: 237
Adjunct
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Adjunct
Joined: May 2008
Posts: 237 |
Either way, with or without water, it's gonna hurt if you drop it on your foot! 
I'd rather ride it than clean it!!!!
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Re: science question
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Joined: Dec 2006
Posts: 7,028 Likes: 8
New Tires
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New Tires
Joined: Dec 2006
Posts: 7,028 Likes: 8 |
Quote:
The more I thought about it, the more I was intrigued by the possibility of water being trapped and kept in the concrete. Forever? If you sqeezed concrete hard enough, would some amount of water be extracted? Does my 60 lb. coarse mix now weigh 68 or so pounds? (Chill out fella's, the concrete is encapsulated in a wooden frame.)(Saw this done in a catapult once, it held up just fine).
The slower the free H2O evaporates the more hydration takes place or is complete. Hydration is the chemical reaction between the mix and water giving off heat that makes concrete hard and strong. That's why "cure' is sprayed on flatwork once it starts to become ridged or tarps are used as a cover.
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
H. L. Mencken
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Re: science question
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Joined: Jan 2005
Posts: 8,639 Likes: 3
Old Hand
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Old Hand
Joined: Jan 2005
Posts: 8,639 Likes: 3 |
To give you a starting point, water weighs 8 lb per gallon. As for how long water stays in concrete, note that the concrete used to make Hoover Dam is still curing.
Let's hope there's intelligent life somewhere in space 'cause it's buggar all down here. -- Monte Python
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Re: science question
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Joined: May 2010
Posts: 5,720
Check Pants
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Check Pants
Joined: May 2010
Posts: 5,720 |
The easiest and simplest elevator is nothing more than a vertical rubber belted conveyor with handholds and toe/foot plates bolted to it. It moves rather slowly, by necessity for safety and you hop on and step off. Not suggested for use after 4 shots of Tequila. You ride one side up and down the other. http://www.elevatorbobs-elevator-pics.com/manlifts_p1.html
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Re: science question
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Joined: Dec 2006
Posts: 7,028 Likes: 8
New Tires
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New Tires
Joined: Dec 2006
Posts: 7,028 Likes: 8 |
Quote:
To give you a starting point, water weighs 8 lb per gallon. As for how long water stays in concrete, note that the concrete used to make Hoover Dam is still curing.
I may be wrong, it's been over 40 years since chemistry class. Much of the water volume reacts with the non-aggregate portion of the mix giving off gas and heat. So all the H and O of the water never "evaporates" off.
Hoover Dam is an amazing thing, anyone ever visiting there should go on the tour. I believe the dam pours were so large they had to run a cooling system through the concrete to dissipate the heat generated from the hydration.
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
H. L. Mencken
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Re: science question
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Joined: Dec 2006
Posts: 7,028 Likes: 8
New Tires
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New Tires
Joined: Dec 2006
Posts: 7,028 Likes: 8 |
Quote:
The easiest and simplest elevator is nothing more than a vertical rubber belted conveyor with handholds and toe/foot plates bolted to it. It moves rather slowly, by necessity for safety and you hop on and step off. Not suggested for use after 4 shots of Tequila. You ride one side up and down the other. http://www.elevatorbobs-elevator-pics.com/manlifts_p1.html
Or he could purchase a used carnival Ferris wheel, very stylish, cutting edge and the neighborhood kids would love him. 
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
H. L. Mencken
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Re: science question
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Joined: Jul 2007
Posts: 6,060 Likes: 6
Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
Posts: 6,060 Likes: 6 |
Quote:
This is of interest to me too, Rich because of the three stories my house is made up of. I live of the top floor which is ground level... the bottom two are built into the side of the mountain I live on. Now, it's only a matter of time and I won't able (or wanting) to use the stairs so an elevator (glorified dumb waiter) will be in order if I stay in this house.
Do you have plans drawn up that you can post so I can have a looky-see at what you are doing?
Getting pretty close to fully operational. Finished the wrought iron "cage" last week, hooked the cables up to the counter weight today and another day fine tuning the balance and it will be done. I'm gonna post some pictures of it soon,along with specs, so get your jeers and constructive criticisms ready. One pre-notation; I've already had the "simple platform" up and down at least two hundred times, hauling freight, a baby grand piano and my dad.
Fidelis et Fortis
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Re: science question
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Joined: Jan 2005
Posts: 6,821
Bar Shake
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Bar Shake
Joined: Jan 2005
Posts: 6,821 |
Here's a pretty cool site for different calculations, I've linked to the concrete section: web pageAnd I would add the water weight to the dry components since concrete doesn't harden by drying but by a chemical reaction that is activated by the water which then becomes a component of the hardened concrete. Note I said hardened, not cured. Concrete continues to cure for decades.
Contra todo mal, mezcal; contra todo bien, también
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Re: science question
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Joined: Aug 2005
Posts: 885 Likes: 2
3/4 Throttle
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3/4 Throttle
Joined: Aug 2005
Posts: 885 Likes: 2 |
Down in the Keys, pretty much all homes are built on stilts as per zoning regulations.. parking underneath the house and living space on 2nd and higher floors. To keep my mother from having to haul groceries and other goods up and down the stairs, we built a very simple dumb waiter out of a chain drive garage door opener. It could handle a few hundred pounds easily and had built in overload protection if you tried to haul too much weight. It was enclosed with a plywood/stucco housing below, and rose up into the pantry upstairs just off the kitchen. Everything needed could be found at the local borg in the garage door section for pretty cheap. It wasn't designed to haul a baby grand piano, but it worked great for groceries, laundry and other bulky stuff you don't want to have to carry up/down stairs Cheers, Brad
To be old and wise, you must first be young and stupid.
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Re: science question
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Joined: Feb 2011
Posts: 2,146
Oil Expert
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Oil Expert
Joined: Feb 2011
Posts: 2,146 |
I'd have to think weight is a variable. The nature of concrete changes with its exposure to moisture. The total weight might be a small change but it IS going to change.
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Re: science question
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Joined: Jul 2007
Posts: 6,060 Likes: 6
Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
Posts: 6,060 Likes: 6 |
Quote:
Here's a pretty cool site for different calculations, I've linked to the concrete section:
web page
And I would add the water weight to the dry components since concrete doesn't harden by drying but by a chemical reaction that is activated by the water which then becomes a component of the hardened concrete. Note I said hardened, not cured. Concrete continues to cure for decades.
Thanks for the link, Bill. Think I'll keep it for further reference. I knew about the slow, total curing time. But I've also heard around, that the concrete we use today will only last for a hundred years or so before starting to deteriorate. Wonder if that's true?
Fidelis et Fortis
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Re: science question
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Joined: Jul 2007
Posts: 6,060 Likes: 6
Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
Posts: 6,060 Likes: 6 |
Quote:
Down in the Keys, pretty much all homes are built on stilts as per zoning regulations.. parking underneath the house and living space on 2nd and higher floors. To keep my mother from having to haul groceries and other goods up and down the stairs, we built a very simple dumb waiter out of a chain drive garage door opener. It could handle a few hundred pounds easily and had built in overload protection if you tried to haul too much weight. It was enclosed with a plywood/stucco housing below, and rose up into the pantry upstairs just off the kitchen. Everything needed could be found at the local borg in the garage door section for pretty cheap. It wasn't designed to haul a baby grand piano, but it worked great for groceries, laundry and other bulky stuff you don't want to have to carry up/down stairs
Cheers,
Brad
Now THAT'S a cool invention! I was surprised it would haul that much weight though. Garage doors are meant to be nearly neutral in weight through the spring tension system.
Fidelis et Fortis
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Re: science question
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Joined: Dec 2006
Posts: 7,028 Likes: 8
New Tires
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New Tires
Joined: Dec 2006
Posts: 7,028 Likes: 8 |
Looking forward to your "report". Got a question, did you construct a elevator pit in the foundation or does it not go to the basement?
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
H. L. Mencken
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Re: science question
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Joined: Apr 2008
Posts: 3,937
Loquacious
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Loquacious
Joined: Apr 2008
Posts: 3,937 |
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But I've also heard around, that the concrete we use today will only last for a hundred years or so before starting to deteriorate. Wonder if that's true?
The concrete I use will continue to CURE for ALMOST a century. SOOO..., I GUESS that means it will then START to deteriorate at one hundred years. 
OTHERS MAY EXPERIENCE DEFERENT RESULTS! 
And you may see me tonight
With an illegal smile
J. Prine
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Re: science question
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Joined: Aug 2007
Posts: 10,730 Likes: 5
Should be Riding
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Should be Riding
Joined: Aug 2007
Posts: 10,730 Likes: 5 |
Quote:
But I've also heard around, that the concrete we use today will only last for a hundred years or so before starting to deteriorate. Wonder if that's true?
file that one under "other peoples problems"
Always remember to be yourself. Unless you suck. Then pretend to be someone else.
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Re: science question
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Joined: Jul 2007
Posts: 6,060 Likes: 6
Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
Posts: 6,060 Likes: 6 |
Quote:
Looking forward to your "report". Got a question, did you construct a elevator pit in the foundation or does it not go to the basement?
Uh, don't have a basement. (Unless something goes really wrong!)
Fidelis et Fortis
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Re: science question
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Joined: Feb 2005
Posts: 20,096 Likes: 2
Fe Butt
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Fe Butt
Joined: Feb 2005
Posts: 20,096 Likes: 2 |
Quote:
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Looking forward to your "report". Got a question, did you construct a elevator pit in the foundation or does it not go to the basement?
Uh, don't have a basement. (Unless something goes really wrong!)
Yeah! I can see now...
"Here lies Rich...who's concrete calculations were just a LITTLE off the mark!"
Yep! Just like a good Single Malt Scotch, you might call me "an acquired taste" TOO.(among the many OTHER things you may care to call me, of course)
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Re: science question
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Joined: Dec 2006
Posts: 7,028 Likes: 8
New Tires
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New Tires
Joined: Dec 2006
Posts: 7,028 Likes: 8 |
Quote:
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Looking forward to your "report". Got a question, did you construct a elevator pit in the foundation or does it not go to the basement?
Uh, don't have a basement. (Unless something goes really wrong!)
So you got a storm shelter?
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats.
H. L. Mencken
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Re: science question
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Joined: Jul 2007
Posts: 6,060 Likes: 6
Worn Saddle
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OP
Worn Saddle
Joined: Jul 2007
Posts: 6,060 Likes: 6 |
Quote:
Quote:
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Looking forward to your "report". Got a question, did you construct a elevator pit in the foundation or does it not go to the basement?
Uh, don't have a basement. (Unless something goes really wrong!)
So you got a storm shelter?
Yeah, actually, there is a 4 ft. crawl space easily available by trap door from inside the house. Additionally, the house has PLYWOOD siding, not that crap wafer board, in addition to steel rods conecting all three floors together in the walls, plus 1/4 inch steel plates at all the outside corner joint as well 1/4 plate, custom fabbed truss hurricane plates. We live on a hill, so I tried to be as proactive about the possibility of tornado as I could.
Fidelis et Fortis
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