# pouring concrete in batches.



## justintime

Due to the nature of project: :sssh: I will have to due all the concrete work myself, I do have a mixer which handles about 3.5 cft at a time ,my ques. is about pouring in batches for I would have to form up small sections at a time
What if any problems might I run into Thanks


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## NaeKid

Due to the lack of information in your question, I am not sure what problems you are expecting to run into when pouring concrete in small batches.

If you are looking at using the concrete to join cinder-blocks for a fence, there should be no problems making a small batch at a time. If you are looking at using the concrete to make an underground shelter that should be water resistant, you will need to coat the seams with concrete sealer (inside and out) and coat all of the outside. You will want to have the concrete "connected" on both sides of the seam with rebar to help create a stronger wall.

If you are looking at using the concrete for a floor or ceiling, it is better to do the pour in as few batches as possible and have the batches all connected via a rebar system over the whole section.


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## justintime

NaeKid sorry about that I had just spent about 1 hour reading all of bunkerbobs post at about midnight , ha ha I thought evey one would know what i was thinking. More info I have a prefab house on a permenent foundation I have started digging a um a root celler. I have done some research on diff building methods I do like no mortor cinder blocks but have not been able to find them . If I was to pour the walls I did not know how well the sections would bond. the floor is going to be 10 ft 12 ft 4 to 6 inches deep but i could only form up so much at a time. 
First) it is under my house not much room getting in and out
SEC) I have to build on a nickle and a dime (POOR)
Thrd) I am not a spring chicken most likely my bad back will only allow me to do so much at a time.


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## jungatheart

If you make something out of concrete and don't do it in one continuous pour, you will get what is called a "cold joint" where the continuous pour stopped. If you must do this, I recommend getting some concrete cement at your hardware store and paint the joint right before the next pour. 

A continuous pour is pretty much mandatory for footings, slabs and bond beams and you might consider hiring someone to help or you will have a weak spot.


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## horseman09

Any time you pour cement onto or against cured concrete and you want the surfaces to adhere, coat the cured surface with muriatic acid. It is cheap and available at any hardware store.


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## allen_idaho

One way around this would be to build a rebar framework inside your concrete pour area. So when you are pouring each section, they will be pretty securely connected. It is something I would definately suggest if you are doing any vertical sections. 

Although depending on how much you need could be pricey.


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## bunkerbob

My experience with pouring concrete came from my last shelter. I did pour in batches, when doing a vertical wall I used a form of course and horizontal and vertical rebar, then when I was near the completion of the pour I set in a 2x4 along the top of the poured section to create a large groove. Then removed the 2x4 after it is set or cured, then move the form up and pour the next batch, thus creating a interlocking groove. Never had a problem with water movement through this joint. Just a quick sketch to show some detail.


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## horseman09

BBob, that is a great idea! I never thought of that!


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## justintime

Hence the name bunkerbob , Thats allmost how they make the dry stack concrete blocks .Sometimes I get my head so far up an idea I cant see what i am doing thanks guys for the input


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## cainm

*i am a concrete finisher 10 yrs*



bunkerbob said:


> My experience with pouring concrete came from my last shelter. I did pour in batches, when doing a vertical wall I used a form of course and horizontal and vertical rebar, then when I was near the completion of the pour I set in a 2x4 along the top of the poured section to create a large groove. Then removed the 2x4 after it is set or cured, then move the form up and pour the next batch, thus creating a interlocking groove. Never had a problem with water movement through this joint. Just a quick sketch to show some detail.


The concrete is going to crack were the two inches goes to whatever size ur wall is making the structure weaker the only way to do it is a countious pour and reber or it won't last long


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## tac803

cainm said:


> The concrete is going to crack were the two inches goes to whatever size ur wall is making the structure weaker the only way to do it is a countious pour and reber or it won't last long


Uh, I think b-bob knows what he's doing. And welcome to the forum.


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## Tjaway6

Making concrete is 1-2-3. One part portland cement, 2 parts sand and 3 parts stone, by volume. You can use more sand and stone but this mix makes great concrete. Make a 4 sided plywood box one foot square on the inside. Use 2x2s on the outside corners. Two opposite corners should be longer to act as handles. Put the box into the mixing vessel. Fill it flush with rock in multiples of three. Lift the box off and rake the stone flush. Next is sand in multiples of two. 1-2-3, 2-4-6, etc. Rake that smooth. Next is the Portland Cement in singles. Rake that smooth. Add a half a gallon of water to one corner. Mix that corner top to bottom. Add more water and pull in more of the dry stuff. Keep mixing in a bit at a time until the entire pan is mixed up. Then shovel it into the form. Start over to keep the pour going. I've mixed over a cubic yard in an afternoon and hardly broke a sweat. One key was to have all the parts ready and close at hand.

The next day remove the forms. Bits of concrete that ended up where they didn't belong can be chipped off easily now.


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