Concrete project: will this work?

[BuilderML]

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

We are talking a 6'x6' slab with one bag mix at a time. If i understand the OP question correctly he is worried about it setting to fast before he can get a finish on it. I wouldn't consider a 3 1/2" slab to be thin. If you are talking about freezing from water being trapped underneath down the road by the plastic. Not something i see happening. Most slabs crack from to wet of a mix and or unstable ground underneath. If your talking about the slab freezing while curing. Lay plastic over the slab once done and cover with a few blankets. If its going to be really cold for a long period of time. Lets say 25* and under covering with heat blankets would be wise.Or wait until you have a few nice days coming up.

 

[Sodo]

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

I'm not convinced that a small mixer is less work than mixing in a wheelbarrow. Actually it sounds like much more work. Lifting, then stuffing all that concrete into the little mixer 14 times, without tipping it over, measure water carefully, one at a time, 14 times, and getting it out 14 times? Loose mix, followed by a stiff mix, on and on, 14 times.

I'd choose 4 or 5 wheelbarrow loads over a small mixer.

Having a tractor I'd choose 2 tractor bucket mixes to be the most efficient. With 80 lb bags instead of 60 you're at 14 bags now. Still reasonable for one guy in half an hour. Those other methods are for non-tractor people. IMHO.

Don't carry 80 lb bags around or lift into a mixer. Set the tractor bucket at tailgate height, move 80 lb bags laterally and slice open right into the bucket. I think your original plan of mixing (6 bags at a time?) in your tractor bucket is the easiest, and more satisfying to use your tractor.

 

[ultrarunner]

With a helper I have poured 810 sacks of 60# for a remote project...

It was the most expensive way to do it cost wise for concrete.

Have to say the used Harbor Freight Mixer did it all... only issue was having to locktite fasteners including the set screw for the pulley key.

8 pallets delivered the first time and 7 the last load and used the tractor to get the material to the job and kept the loader the same height as the mixer so no lifting only moving and dumping.

Drew water from a garbage can using a bucket to measure for consistency.

A sewer contractor working for the city would pour a yard of concrete into their dump truck and then dump into their loader bucket for transport into the rough... said they always did it this way.

 

[Streetcar]

Concrete is not waterproof, the plastic will stop the water from moving through the slab. The trapped water can freeze. The only time I see plastic under concrete in Ohio is when removing severely deteriorated slabs or as use as a bond breaker. I try to have slabs a minimum of five inch thick so 3 1/2 is thin for me.

 

[FredH]

Rarely use pre mix bags , I always get sand / gravel mix from a local rock place and mix it 4 shovel fulls of that with 1 cement shovel . Add water accordingly . Most of the time I mix 16 to 4 , which when dumped into a double tire wheelbarrow is about all you want to push around . Last slab I did was 14' x 8' x 5.5" . Wife helped scree it off but the mixing , dumping was all me . That shed still stands this day without a crack any were .

For that amount , I think you will be fine . Don't mix to wet or to dry . The way you talk about dumping it into your bucket will work since you will have some settling of the mix . but no water loss . So before you dump into your form , just use a garden hoe to stir it a little before dumping .

Images below are similar to the type mixer I have

Fred H.

 

[FTG-05]

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.

The comments made before about taking more than one minute per bag/batch plus being able to work during the idle time of mixing lends me to discard using the tractor bucket idea and just pour direct. I throw a bag or two, hit it with water and while it's mixing, move/scree/whatever with the prior batch in the pad.

Using plastic on the bottom, I like it! There's no chance of freezing temps in the next week or so, so that's not a problem. I live in SC TN, not the Siberian wastelands of WI/MI/MN/SD etc.

Thanks,

 

[FTG-05]

I'm not convinced that a small mixer is less work than mixing in a wheelbarrow. Actually it sounds like much more work. Lifting, then stuffing all that concrete into the little mixer 14 times, without tipping it over, measure water carefully, one at a time, 14 times, and getting it out 14 times? Loose mix, followed by a stiff mix, on and on, 14 times.

I'd choose 4 or 5 wheelbarrow loads over a small mixer.

Having a tractor I'd choose 2 tractor bucket mixes to be the most efficient. With 80 lb bags instead of 60 you're at 14 bags now. Still reasonable for one guy in half an hour. Those other methods are for non-tractor people. IMHO.

Don't carry 80 lb bags around or lift into a mixer. Set the tractor bucket at tailgate height, move 80 lb bags laterally and slice open right into the bucket. I think your original plan of mixing (6 bags at a time?) in your tractor bucket is the easiest, and more satisfying to use your tractor.

Not trying to discount your input, I'm not, I really appreciate it. The difference between the mixer vs. the wheelbarrow is the mixing. No matter what, I still have to move the bag, cut the bag, drop the bag contents and then add water. The question is: do I want to flip a switch or stand there and try to move +80 lbs of wet concrete while I could be doing something else.

And Plus: I know where the mixer is, I'm not sure where my wheelbarrow is (that's what the FEL is for.....).


ETA: I just saw your comment about mixing in the FEL, missed it the first time. I don't plan to mix in the FEL. My original plan (and what this thread started out asking about) was mixing one/two bags at a time in the mixer, dumping it into the FEL; then when all 18 bags were mixed and in the FEL, move and dump the 18 mixed bags in the FEL into the pad forms. Sorry for the confusion.

Thanks,

 

[roadhunter]

You will be fine. 6x6 will be no problem for 1 person.

 

[roadhunter]

I'm not convinced that a small mixer is less work than mixing in a wheelbarrow. Actually it sounds like much more work. Lifting, then stuffing all that concrete into the little mixer 14 times, without tipping it over, measure water carefully, one at a time, 14 times, and getting it out 14 times? Loose mix, followed by a stiff mix, on and on, 14 times.

I'd choose 4 or 5 wheelbarrow loads over a small mixer.

Having a tractor I'd choose 2 tractor bucket mixes to be the most efficient. With 80 lb bags instead of 60 you're at 14 bags now. Still reasonable for one guy in half an hour. Those other methods are for non-tractor people. IMHO.

Don't carry 80 lb bags around or lift into a mixer. Set the tractor bucket at tailgate height, move 80 lb bags laterally and slice open right into the bucket. I think your original plan of mixing (6 bags at a time?) in your tractor bucket is the easiest, and more satisfying to use your tractor.

good advice^^

 

[FTG-05]

And now to update on today's activities:

Common sense, if not some semblance of basic intelligence prevailed and I decided to split up the pad prep/rebar install into one day and then pour the pad another day.

So here's today's progress in pics:

Took me quite a while to get the pad prepe'd the way I liked it. It's amazing how much drop off there is in a seemingly minor slope of ground. Oh well, enough whining! These pics are pre-tamping (you can see my tamper in one of the pics).

Rebar framework installed (temporarily):

Rebar complete:

While preping the pad, I had tampered it down, then watered it to find any high spots. That turned out to be a mistake: it turned it into a soupy mess!

I'll let it dry out overnight, remove the rebar, install some gravel, then retamp it down again. I think the rebar is a little too high at the upper end (the area where you sit) and I'll fix that tomorrow. It also appears that it will be closer to 4" thick instead of 3.5" Yea, Yea, I know: No Whining!!!!