Concrete project: will this work?

[FTG-05]

I'll be pouring a 6'x6' concrete pad tomorrow, 3.5" thick. Calculator says it will be about 10.5 cu. ft. or just under 18 bags of concrete. I have the HF concrete mixer, works pretty well but only for one bag at a time.

What I'd like to do is mix all the concrete at once, dropping each mixed bag into my tractor bucket (L4330 with a 1/2 cu yd bucket) and then drop the whole bucket load at once at the pad. It usually takes about a minute or so for each bag of concrete, perhaps I can add a half bag, I'll have to see if that will work. So we're talking probably 20-30 minutes of bag mixing from the first bag to the last bag.

Will this work or do I risk having the concrete start to harden and cure while in the bucket?

Thanks for any suggestion, comments etc.

 

[CurlyDave]

I would hold off on doing this tomorrow unless you have someone who is very experienced to help you. Concrete is hard work to put in, easy to make a fundamental mistake, and if you do, ugly to look at for a long time.

1. One minute in the mixer does not seem like long enough to me. It usually takes several minutes to get a good, uniform mix in my mixer.

2. How are you going to finish the concrete? Typically you need to screed concrete (evens out the top surface), bull float (levels and further evens out the top surface), and then trowel (smooths and further evens out the surface). There is a special tool to make the rounded edge usually seen on a concrete pad. For an amateur, the safest bet is to add a light broom finish after the trowel, which hides a lot of imperfections.

3. Have you considered getting a concrete buggy (looks like a miniature concrete truck, but is really a trailer) or even a gondola (no mixing capability, but it does have hydraulic jack type of device to lift and empty the tub)? These take a lot of work out of the mixing.

4. The weather is getting pretty cool now, the trouble I see you having is not the concrete curing too quickly, but having to wait a very long time for the concrete to set up well enough to finish it.

5. Don't dump it all at once in a big pile. Spread it out as evenly as you can which will make the screeding easier.

You should strongly consider hiring a professional finisher. He will tell you how to set up the pad (gravel underneath) re-bar, and forms. Inspect your work on this, and direct the actual concrete placement and then finish it off. Once you have experience with the first pad, future concrete projects will be much easier.

I have poured a lot of concrete in my life, not a pro by a long shot, but a very advanced amateur. Ready mix is almost always less expensive than mixing bags yourself, stronger because of a better mix, and less expensive. Even most general contractors will get a specialized subcontractor for concrete, or at least hire a finisher. I have placed several hundred yards of concrete in dozens of pours, and I always use a finisher.

 

[bcp]

I did a 7x11 with the HF mixer, 60lb bags and two people. One mixing; one hauling, placing, and spreading; both screeding as needed. you can't wait for the whole thing to work the whole surface, you sort of work it as you go, and you may have several steps going at once. The result was satisfactory. The work was frantic.

Bruce

 

[Cat_Driver]

I did just what you are thinking and it worked fine. I had more bags and a bigger area. I had one guy break the bags add water and dump in my bucket. I drove over dumped, came back for the next load repeated till done. The mixer will do more if you push it. Several times I waited for a two or three dump before I travelled. It was over 100 degrees when I did mine and it never hardened up on me. In fact I still needed to wait for it to settle before finishing.
If it's not too late add some fibers, I did to mine and sure keeps the cracks out.
Not a job to do alone for sure, but sure saved me a lot of money.

 

[Sodo]

I would do it similar to this wheelbarrow method.

The wheelbarrow method that I learned from my father-in-law who was a contractor (RIP):

1) Three 80 lb bags, fill a 5 gal plastic bucket slightly more than half full, dump the water into the wheelbarrow.
2) dump the first 80 lb bag in, it mixes easily (with a hoe)
3) dump 2nd 80 lb bag in, still mixes easily, still very soupy, pretty easy mixing.
4) dump 3rd 80 lb in, while spreading it over the top of the whole wheelbarrow. So only the last bag is a difficult mix, and note there is no dry cement on the bottom of the wheelbarrow with this method.

The water level stated is for three 80 lb bags, sounds like you are using 60lb, so it would be four bags for that amount of water. Point being that since mixing can be strenuous arrange to do MOST of the mixing with a very soupy mix.

Seems like in a tractor bucket you could double this method, for example mix eight 60lb bags. Where maybe the first 6 bags are easy soupy mix and that last two get to be difficult. Then dump it in your forms from the bucket, that would be satisfying.

 

[FTG-05]

I would hold off on doing this tomorrow unless you have someone who is very experienced to help you. Concrete is hard work to put in, easy to make a fundamental mistake, and if you do, ugly to look at for a long time.

1. One minute in the mixer does not seem like long enough to me. It usually takes several minutes to get a good, uniform mix in my mixer.

2. How are you going to finish the concrete? Typically you need to screed concrete (evens out the top surface), bull float (levels and further evens out the top surface), and then trowel (smooths and further evens out the surface). There is a special tool to make the rounded edge usually seen on a concrete pad. For an amateur, the safest bet is to add a light broom finish after the trowel, which hides a lot of imperfections.

3. Have you considered getting a concrete buggy (looks like a miniature concrete truck, but is really a trailer) or even a gondola (no mixing capability, but it does have hydraulic jack type of device to lift and empty the tub)? These take a lot of work out of the mixing.

4. The weather is getting pretty cool now, the trouble I see you having is not the concrete curing too quickly, but having to wait a very long time for the concrete to set up well enough to finish it.

5. Don't dump it all at once in a big pile. Spread it out as evenly as you can which will make the screeding easier.

You should strongly consider hiring a professional finisher. He will tell you how to set up the pad (gravel underneath) re-bar, and forms. Inspect your work on this, and direct the actual concrete placement and then finish it off. Once you have experience with the first pad, future concrete projects will be much easier.

I have poured a lot of concrete in my life, not a pro by a long shot, but a very advanced amateur. Ready mix is almost always less expensive than mixing bags yourself, stronger because of a better mix, and less expensive. Even most general contractors will get a specialized subcontractor for concrete, or at least hire a finisher. I have placed several hundred yards of concrete in dozens of pours, and I always use a finisher.

Good stuff, I'll try to answer as best I can:

1. One minute was off the top of my head for a minimum time per mixer load. I've used the mixer a couple times already for smaller projects (deer pole and shooting table top). Typically it would take more than a minute, but then I wasn't in a hurry to do almost 18 either....

2. Finishing would be with a 2x4 to scree it, then a concrete finishing tool I have plus the edger you talked about.

3. I live out in the sticks, the nearest concrete place is over 20 miles away. And it's only 10.5 cu ft.

4. I poured the table top at 50 degrees and it got down to 30 that night; it didn't freeze though because it was a) in my shop and b) I had a small heater pad underneath the top with plastic on top. It still hasn't cured yet, but that's ok, I'm not in any hurry. It's about 60 already hear this morning (9 AM CST) and it will be pretty warm all the rest of this week.

5. Good point. Using the FEL, it should be fairly easy to dump a little at a time.

There will be some gravel under it not a lot. Rebar will be 1/2" welded frame with some left over hog panels also.

This project is for a concrete shooting bench: How to Build the Ultimate Shooting Range Bench | RifleShooter

And here are some pics of the shooting bench table top:

 

[FTG-05]

I did just what you are thinking and it worked fine. I had more bags and a bigger area. I had one guy break the bags add water and dump in my bucket. I drove over dumped, came back for the next load repeated till done. The mixer will do more if you push it. Several times I waited for a two or three dump before I travelled. It was over 100 degrees when I did mine and it never hardened up on me. In fact I still needed to wait for it to settle before finishing.
If it's not too late add some fibers, I did to mine and sure keeps the cracks out.
Not a job to do alone for sure, but sure saved me a lot of money.

Ok, good to know, thanks.

Where do you get fibers? I've NOT seen it at the usual suspects (Lowes/HD, etc.); although I've never looked either.


Sorry Sodo, but no! I got the HF mixer so I wouldn't have to use a wheelbarrow!!! It's bad enough lifting and moving the 80 lb bags around (the only size my local hardware store sells.

Thanks,

 

[EddieWalker]

I just poured a 12x12 pad 7 inches thick with footings over a foot deep around the perimeter a couple of weeks ago. I did it on a Sunday because that's the only time I had available, which meant I had to mix it myself instead of having a truck come in with it. I would have preferred the truck, but that just wasn't possible. I made it that thick because of the slope of the ground I'm working on. I also wanted it to be a bit higher because there will be horses around it and I'm nervous about mud being next to the building for extended periods of time, which might lead to termites or other issues.

I bought two pallets of 60 pound sacks. 54 sacks on a pallet. I also used another 28 sixty pound sacks that I had stored in my shop to do this. I poured three sacks into my mixer at a time, then dumped it into my wheelbarrow and started at the farthest corner. I then worked my way closer, going from one side to the next. Every ten loads, give or take, I ran my scree board over the concrete and troweled it smooth. Temps where in the 60's, so it was a perfect day. I like to mix my concrete on the dry side, so that made it a little harder, but still doable. It was a very long day, but very doable for one person working alone.

The finish isn't what you would expect from a pro, but it's smooth enough to sweep clean. I'm not good enough to get it perfect. That takes a lot of practice, which is something I'll never put the time into doing. For bigger pours, I hire it out.

Eddie

 

[BuilderML]

You'll be fine mixing one bag at a time. You have to work with what you have. Have the mixer right next to the slab to pour right in and your good to go. One thing i would do to slow the process down to give you more working time is lay plastic under your slab. Makes a world of difference doing it the way you'll be doing it.

 

[Streetcar]

You'll be fine mixing one bag at a time. You have to work with what you have. Have the mixer right next to the slab to pour right in and your good to go. One thing i would do to slow the process down to give you more working time is lay plastic under your slab. Makes a world of difference doing it the way you'll be doing it.

Plastic under the slab can lead to problems with freezing temperatures , the plastic traps water in slab. For thin slab curing is important. Either a sealer, or wet cure will work