# Pouring concrete a little at a time as a DIY



## joecaption (Nov 30, 2011)

Very poor plan in my option.


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## bbo (Feb 28, 2010)

sounds good until you get to the second section and realize how much work the first was and you have to do it 36 times.


online calculator tells me that's 359 80 lb. bags.


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## mtr_can (Jul 17, 2011)

joecaption said:


> Very poor plan in my option.


Why do you say that? I realize all the added work and time makes this a non-option for most.


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## mtr_can (Jul 17, 2011)

bbo said:


> sounds good until you get to the second section and realize how much work the first was and you have to do it 36 times.
> 
> 
> online calculator tells me that's 359 80 lb. bags.


That's the downside :laughing: Nobody said sweat equity was easy right?

But I am curious do you need specific joints made in the concrete forms? I assume you need to tie each section together with rebar.

What I don't know is whether you would need construction joints (assume so) and also whether you would need bonding agents to bond new sections of wet to dry sections of previously poured?


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## stadry (Jun 20, 2009)

yes, of course it can,,, but joe's right, too - a p-p plan  having said that, a lot depends on where your' where ',,, if so, if we knew that, it could help,,, motive & slab use might also help,,, after all, much in life IS possible - recommended ? not on your life :no:

if we HAD to do it by hand, i'd bi*** - we'd do w/2 guys, mixer, & 6' x 6' slabs ,,, your 3' x 3' slabs req 9b neat - maybe 10b @ 80# w/some waste

why rebar OR tie bars ? construction jnts are auto formed when pouring 1 slab against another so you don't have to do anything - they just happen,,, you'll not be able to bond new conc to old as you think,,, anything's possible IF you don't know what you're doing or don't understand the issues.

the late atlanta humorist, lewis grizzard, said often,,,, forget the exact quote but it included brains, God, & ****-ants,,, on this forum, ' most ' have more brains


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## joecaption (Nov 30, 2011)

Why 8" thick? That's double the normal thickness of a slab.
http://www.concretenetwork.com/concrete/howmuch/calculator.htm
#1, Do you really want to pick up, handle, store this much material?
#2, Having to take the time to have to go back and reset up for the next pore that many times.
#3, No way to keep it all level with the changing seasons.
#4, Much harder to maintain the needed slope.
My guess is you have never pored concrete before and think some how your going to be saving money by doing it this way.


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## Daniel Holzman (Mar 10, 2009)

Many slabs are not structural. For example, most basement slabs are four inches thick, and serve no structural purpose. Their function is to provide a smooth, hard, durable floor. Non-structural slabs can be constructed in pieces, and there is no need to use rebar. The topic of rebar in slabs has been discussed many times on this forum, with respect to walls, slabs, sidewalks etc. There are of course numerous opinions about the need for rebar, and I suggest you review the threads if you want more information on this controversial topic. My point is that rebar in a four inch thick slab cannot provide any structural value, since the bars need a minimum of 1-1/2 inch cover on the top, and 2 inches on the bottom, so effectively the bars must be placed at the center (neutral axis) of the slab. Since the neutral axis carries zero stress, the bars perform no significant structural function in such a slab. They may reduce cosmetic cracking, but those who have done this type of work will tell you that the most important factors in thin slab cracking are preparation of the subgrade, quality of the concrete, care in curing the concrete, proper finishing of the concrete, and use of control joints.

For a structural slab, typically a minimum of 6 inches thick, or a structural wall or beam, it is not desirable to make multiple pours. Since the stress must be carried across the joints in a structural slab, it is necessary to properly lap the rebar, and make the joints carefully. On large buildings, if it is absolutely necessary, structural joints may be included in the pour, but it adds work and reduces the ultimate strength of the pour at the connections. At least in my experience, designers often specify monolithic pours for structural mats or slabs, and they go to a lot of trouble to insure proper curing of the concrete, up to including cooling pipes in the concrete to prevent overheating.


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## stadry (Jun 20, 2009)

daniel, i always thought they kept the walls in place & parallel :whistling2: as i recall, aci doesn't recommend steel in 4" slabs as there's not at least 2" of cover over the bar,,, steel adds little in compressive strength however it does add greatly to flexural strength as i was taught,,, welded wire mesh serves 3 purposes - 1st, its adds necessary strength while the slab is in tension; & 2nd, it holds the broken pieces together after the conc cracks; & 3rd, let's the guys get overtime when they have to remove slabs w/wire :laughing:

nice post, daniel :thumbup:


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## Colbyt (Jan 27, 2014)

mdo11 said:


> Could a large concrete slab (or wall) be poured a little at a time by a single person with proper formwork and tying section by section together with ample rebar?



No reason it can't. Sure is a lot of work. 

If doing walls pour an entire vertical section as fast as you can mix it. Build your form and then block it off to pour the fist vertical section. I've done several small retaining wall / curbs this way.

Slabs are a bit difficult to keep level and pretty when pouring in sections.

4" for a slab is almost always enough. More is not better because the weight can become a problem.


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## Canarywood1 (May 5, 2012)

"They may reduce cosmetic cracking, but those who have done this type of work will tell you that the most important factors in thin slab cracking are preparation of the subgrade, quality of the concrete, care in curing the concrete, proper finishing of the concrete, and use of control joints."

And i'll add one more factor to Daniel's excellent post, placement of the concrete,in other words DO NOT add enough water to make a sloppy mix,thinking it will give you added time of workability,it's best to place at a 4 inch slump.


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## jomama45 (Nov 13, 2008)

W/o getting into this too deep, consider this:

You'll need about 400 - 80# bags at about $5.00 a piece = ~$2000.00

OR

You'll need about 8.25 yards of ready-mix concrete delivered to your site at about $120.00 a yard (price varies vastly depending on location) = ~$990.00.

Seems like a waste of effort and time to me, not to mention the ready-mix concrete is generally superior overall product. Also, if you live in a freeze-thaw prone area, you won't get the needed air-entrainment from a bag mix..........


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## Mort (Nov 26, 2008)

I often wonder on this site what everybody is so afraid of when it comes to ordering a concrete truck. For half the price and a couple hours of hard work (as opposed to a couple months), you're done and drinking beer. 

The only way I can see the advantage in doing it in sections is if you have a deal with the concrete plant to get their leftovers from them.


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## stadry (Jun 20, 2009)

the min load here's 5cy & we're @ the mercy of the plant re ' WHEN ' we'll get it 'cause we don't buy enough to be a major customer,,, IF we want to piggy-back & get a hot load, its easier for delivery but a pita for the guys to work & place,,, too much of a gamble for me,,, beer makes MUCH more sense :drink:


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## Canarywood1 (May 5, 2012)

"The only way I can see the advantage in doing it in sections is if you have a deal with the concrete plant to get their leftovers from them.[/QUOTE]"



I wouldn't call getting leftovers the way to go,as you don't know exactly what your getting or how old it is,have you ever seen a flash set???


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## Mort (Nov 26, 2008)

Canarywood1 said:


> I wouldn't call getting leftovers the way to go,as you don't know exactly what your getting or how old it is,have you ever seen a flash set???


True, you don't know what you're getting, but it can't be that much worse than bags. And besides, dude's not building a suspension bridge. 

And as for flash set, yes I have. We did some paving in the middle of I-5, with the catch being it had to be open to traffic the next morning. We designed a paving mix with 14% Non CC accelerator that made design strength in 4 hours. The first time I went to do an air test I got a phone call, and after it had been in there for 7-8 minutes, it flashed in my wheel barrow. The mix was 45 minutes old at the most.


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## Gary in WA (Mar 11, 2009)

Did they ever give your phone back to you, how's that 6" deep barrow workin' for you..... 

Gary


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## Canarywood1 (May 5, 2012)

Well the same thing can happen with a load that's been in the drum too long,i've seen it come down the chute and set when it hit the form instantly,not a pretty sight.


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## Mort (Nov 26, 2008)

Gary in WA said:


> Did they ever give your phone back to you, how's that 6" deep barrow workin' for you.....
> 
> Gary


I got it out of the wheelbarrow just fine (sledge hammers are your friend), its the air pot I was worried about. Luckily I hadn't started my air test yet. When I did manage to get an air test, I got the results and immediately dumped it out. It was already starting to go off then. 

We make sure the drivers have a bottle of Coke when they haul that mix, which thankfully isn't very often.


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## Canarywood1 (May 5, 2012)

Mort said:


> I got it out of the wheelbarrow just fine (sledge hammers are your friend), its the air pot I was worried about. Luckily I hadn't started my air test yet. When I did manage to get an air test, I got the results and immediately dumped it out. It was already starting to go off then.
> 
> We make sure the drivers have a bottle of Coke when they haul that mix, which thankfully isn't very often.


 

You would need a lot more than a bottle of coke for a load,probably more like a 50lb bag or two of sugar.


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## concretemasonry (Oct 10, 2006)

My friend has 100 or so dumpers/trucks and has at least 2 or 3 10# bags of sugar in every one of them. As long as they can get drum roratation they can get the mud out easier instead of buying a new 10 or 12 cy drum.

Dick


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## stadry (Jun 20, 2009)

sugar & water was the original retarder, wasn't it ?


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## Canarywood1 (May 5, 2012)

concretemasonry said:


> My friend has 100 or so dumpers/trucks and has at least 2 or 3 10# bags of sugar in every one of them. As long as they can get drum roratation they can get the mud out easier instead of buying a new 10 or 12 cy drum.
> 
> Dick


In the 35 years I worked in the redi-mix industry,i never once was able to get sugar into a load about to set up,mainly because the drums were chain drive operated by power takeoff,then they went to separate engine drive, if you couldn't get the engine to turn over,sugar did you no good,but when hydraulic drive came along we had it made,our mechanic's made up a set of long hydraulic hoses they could connect from an operating truck to the pump on the one that was broke down,no more loads set up in a drum.

By the way,if you get sugar into the load it will still set up ,it's just a lot easier to break it out when you do start cleaning it out,you just don't buy a new drum as they are pretty expensive.


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## landfillwizard (Feb 21, 2014)

Hey Mort,

Ever use a rollameter for low density concrete?


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## Kaleyh (Mar 1, 2014)

Ummmmm I would hire someone to give you a quote first and take a look at their ideas before starting this 'piece by piece' plan of action


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## de-nagorg (Feb 23, 2014)

Maybe they are planning to pour in an area that has no access by truck, or car or motorized vehicle. 

Sounds like maybe a doomsday prepper type of scenario. 

or at least somewhere way off the grid.

ED


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## Mort (Nov 26, 2008)

landfillwizard said:


> Hey Mort,
> 
> Ever use a rollameter for low density concrete?


Never needed to. Only job we used lightweight concrete on was almost finished when I was doing QC. I learned how to use it for my ACI test, but that's it.


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