Posted: 6/26/2010 7:11:14 AM EDT
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80 lb bags of Quickrete are a little over 1 cubic foot in volume.
I have to mix about 16 bags to make a pad for my new heating fuel tank. I would guess I want a medium mix, not too dry, not to soupy. How much water should I use?.......i want to measure it out to make it faster and a more consistent mix. Any expert here?? 
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| Having mixed 44 bags recently, all I can tell you is that if you're mixing 16 bags by hand you're gonna a be a worn out mf'er. Rent a mixer, a big one. I used one that held 4 bags. Use a sprayer on a hose put about 2 gallons or so of water in the mixer, put one bag in at a time and run the mixer. Adjust your water content after the last bag is in. If you are hell bent on mixing it by hand, the easy way I found, if you don't by a mixing tub, is to use a kiddy pool, a hoe & a shovel. |
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Whenever I mix concrete I keep an empty 5 gal bucket for the water. I usually end up starting with about 2.5 gals of water to two bags of mix. I adjust the amount of water I use after I see how the first mix goes. Good excuse to post some pics.    I ended up having to do this by the bag. I ended using about 50 lol. |
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Quoted: You dont want whats left over ! If it was mixed at the site or while in transit , you have X amount of time before it takes off, depending on mix ,psi, temp , chemicals and other factors. every once in a while when getting a short load "under 10 yards" we will get a load that was left over from someone elses pour. Its okay for footings and such but its hit and miss if your pouring something that needs to be "finished".
I've heard you can sometimes get deals from concrete truck companies for the leftovers in the truck at the end of the day. |
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Quoted:
I eye ball it too. After awhile you just know what you want it to look like. Trial and error. 16 bags seems like a lot. Is calling for a truck not an option? Scheduling is the issue , I cannot get off work during the week and it is in a difficult location and would have to put in a wheel barrow and dumped anyway. I can mix it pretty good in a wheel barrow with a hoe..........That where the Wife come in!!! 
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Adding some Portland Cement into the mix is not a bad idea.
Quickcrete in the bag is ghetto concrete, because they short you on the portland cement. A 1 pound coffee can of portland added to each bag makes it a lot stronger, and a bit easier to finish. Only catch is...I've only seen portland cement in 80 pound bags, so there will be quite a bit left over. I have some you can use if you want to pick it up.
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| if you're going to do that just get the premixed sand/gravel from a sand and gravel place and mix your own - a lot cheaper that way over quikrete. In my small mixer (harbor freight $150 and has lasted forever) its about 15 shovels of sand/gravel mix and half a 5 gal bucket of Portland. Yep - eyeball the water - it'll vary with moisture in your sand/gravel, etc. |
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Quoted:
I've heard you can sometimes get deals from concrete truck companies for the leftovers in the truck at the end of the day. Wrong. It would be worthless by then. Sometimes customers over-order, but you'd have to be right there and ready to pour to get a "deal" (probably between you and the driver, on the down low) I used to drive a mixer. Our company also manufactured septic tanks. We used leftovers (usually with a little more mixed in) to pour tanks with. OP, I haven't priced sackrete lately, but I think concrete delivered (ready mix) is about $100/cu. yd now. Probably a 3 yard minimum too. |
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If you make your own concrete a 3-2-1 mixture (by weight) of stone, sand, and cement will be decent. A water/cement ratio (by weight) of .55 will give a good compromise between strength and workability. Example - You need 16 cf of concrete. Unit weight is ~150lb/cf, meaning you need 2400lb of concrete. Cement (1/6) = 400 lb Sand (2/6) = 800 lb Gravel (3/6) = 1200 lb water (given a .55 w/c ratio) = 220 lb (~8.33 lb/gal) -> 26.4 gallons |
| depends on where you live and what kind of weather.....im an electrician and regularly use quickrete]drypack... if pouring in a form i mix wet......almost soupy..., make sure you have a moisture barrier/plastic and a good base...try to build the form first and then lay the plastic so its almost a swimmingpool....the water will evaporate no matter what and its a whole lot easier to wait for it to dry then to try and mix more water in after its in the form....i would however reccomend renting a mixer otherwise it will be a bitch.... |
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Quoted: Per their site, a 4' X 8' X 6" slab should be 14 bags.......16 cubic feet of slab.or an i messing up my simple math? its 16 cf, but their site says 27 80# bags are needed eta - the input is for square feet needed, then you pick the thickness. you are entering the volume |
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Quoted:
Quoted:
Per their site, a 4' X 8' X 6" slab should be 14 bags.......16 cubic feet of slab.or an i messing up my simple math? its 16 cf, but their site says 27 80# bags are needed eta - the input is for square feet needed, then you pick the thickness. you are entering the volume good save |
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Quoted: If you make your own concrete a 3-2-1 mixture (by weight) of stone, sand, and cement will be decent. A water/cement ratio (by weight) of .55 will give a good compromise between strength and workability. Example - You need 16 cf of concrete. Unit weight is ~150lb/cf, meaning you need 2400lb of concrete. Cement (1/6) = 400 lb Sand (2/6) = 800 lb Gravel (3/6) = 1200 lb water (given a .55 w/c ratio) = 220 lb (~8.33 lb/gal) -> 26.4 gallons unit wt~150 lb/cf––-no air entrainment ? , he's pouring something outside w/c ratio @ .55 seems high 400lbs of cement for 60% of a cubic yd ? over designed jmvho |
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Quoted: Quoted: If you make your own concrete a 3-2-1 mixture (by weight) of stone, sand, and cement will be decent. A water/cement ratio (by weight) of .55 will give a good compromise between strength and workability. Example - You need 16 cf of concrete. Unit weight is ~150lb/cf, meaning you need 2400lb of concrete. Cement (1/6) = 400 lb Sand (2/6) = 800 lb Gravel (3/6) = 1200 lb water (given a .55 w/c ratio) = 220 lb (~8.33 lb/gal) -> 26.4 gallons unit wt~150 lb/cf––-no air entrainment ? , he's pouring something outside w/c ratio @ .55 seems high 400lbs of cement for 60% of a cubic yd ? over designed jmvho |
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Just to reiterate what others have said....
1) 80 # of concrete mix is the equivalent of .6 (6/10) of a cubic foot. 2) The amount of water for maximum strength is 2.8 to 3 quarts per 80# bag. That gives a stiff mix, I generally use almost a gallon for workability. I know I'm giving up a little strength, but I'd rather have no voids and a finishable surface. And if you really require a specific strength, you need to be buying transit-mixed anyway. 3) Qwikrete is really in need of more portland. I won't hesitate to put a shovelful of cement per bag in the mix, if that's the only brand I can get. Sakrete is MUCH better. 4) If you're only getting a yard or so, you'll pay out the ass in short-load fees. But it may still be cheaper, and will definitely be easier and faster, than mixing your own. 5) If you're intent on mixing it yourself, forget about the bagged stuff, and just buy sand, gravel, and Portland. Masonry suppliers can tell you who to call for a small load, or you could get it all in 1 or 2 pickup loads for half the price of the bagged stuff. |
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Originally Posted By AR-10: Adding some Portland Cement into the mix is not a bad idea. Quickcrete in the bag is ghetto concrete, because they short you on the portland cement. A 1 pound coffee can of portland added to each bag makes it a lot stronger, and a bit easier to finish. Only catch is...I've only seen portland cement in 80 pound bags, so there will be quite a bit left over. I have some you can use if you want to pick it up. Great idea. Cement comes in 94 lb bags. Now days they sell half bags of 47 lbs. Quoted: Home run!Just to reiterate what others have said.... 1) 80 # of concrete mix is the equivalent of .6 (6/10) of a cubic foot. 2) The amount of water for maximum strength is 2.8 to 3 quarts per 80# bag. That gives a stiff mix, I generally use almost a gallon for workability. I know I'm giving up a little strength, but I'd rather have no voids and a finishable surface. And if you really require a specific strength, you need to be buying transit-mixed anyway. 3) Qwikrete is really in need of more portland. I won't hesitate to put a shovelful of cement per bag in the mix, if that's the only brand I can get. Sakrete is MUCH better. 4) If you're only getting a yard or so, you'll pay out the ass in short-load fees. But it may still be cheaper, and will definitely be easier and faster, than mixing your own. 5) If you're intent on mixing it yourself, forget about the bagged stuff, and just buy sand, gravel, and Portland. Masonry suppliers can tell you who to call for a small load, or you could get it all in 1 or 2 pickup loads for half the price of the bagged stuff. |
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Quoted: Quoted: Quoted: If you make your own concrete a 3-2-1 mixture (by weight) of stone, sand, and cement will be decent. A water/cement ratio (by weight) of .55 will give a good compromise between strength and workability. Example - You need 16 cf of concrete. Unit weight is ~150lb/cf, meaning you need 2400lb of concrete. Cement (1/6) = 400 lb Sand (2/6) = 800 lb Gravel (3/6) = 1200 lb water (given a .55 w/c ratio) = 220 lb (~8.33 lb/gal) -> 26.4 gallons unit wt~150 lb/cf––-no air entrainment ? , he's pouring something outside w/c ratio @ .55 seems high 400lbs of cement for 60% of a cubic yd ? over designed jmvho I didn't intend to stomp on your post, you're right for a basic home type do it yourself project. I was thinking like I was trained and the cost of someone hauling the crushed stone, sand and the obvious amount of work required to hand mix that, glad it's not me. I would though call a ready mix plant and just inquire if they have any loads coming my way in the near future and see if they would ad an extra yd for him, that way they might not charge a small load fee. It's been a whlie since I spoke with anyone about mix designs, you know your stuff !!!  |
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Quoted: I would though call a ready mix plant and just inquire if they have any loads coming my way in the near future and see if they would ad an extra yd for him, that way they might not charge a small load fee. It's been a whlie since I spoke with anyone about mix designs, you know your stuff !!! And we (concrete producers) dont do that because... The first guy measured 20x20x6 but its really 20x20x7 and when he is done so is your yard. And we would be screwing ourselves out of a small load (9 yds min) fee. We dont compete with ourselves for "Joe COD". Your best bet to get a small amount from "us" is to bring in a pickup truck with a tarp int he back and buy a yard. When we load a truck we will pull out and give you your yard. Fresh mud, good slump, decent weather, short drive and fairly quick placement you should have 1.5-2 hours from beginning to end until you better be done. |