# Mixing different brands of concrete together



## JustScrewIt

I want to extend the walkway leading up to my house another 6" and wanted to know if I could just use up a few half empty bags that I have leftover from various past projects. The thing is, they're not all the same brand or same type, and I'm not sure what effect mixing them (dry) would have on the final product. Here's what I have to work with:

- ~15 lbs of Quikrete Fast Setting
- ~20 lbs of Sakrete Maximizer
- ~10 lbs of Rapid Set Cement All
- ~15 lbs of Quikrete Crack Resistant
- ~10 lbs of Portland Cement

I'm just trying to make use of what I got while also saving myself a trip into town (and saving the planet too OF COURSE... )

BTW, the 6" add-on needs to be 3 feet wide x 4in. thick... Which I'm guessing will take about 50-60lbs right?


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## Ron6519

Such a cheap ass idea. Buy fresh concrete for the job and screw the planet.


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## Colbyt

15 
20 +
10 +
15 +
10 +
--------------------------
70 =

Does not even equal a single 80 pound bag. Skip lunch and buy a fresh bag, mix in a little of that Portland to increase the PSI.


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## SeniorSitizen

Just mix it all together and you'll have some goooood stuff that no one has ever tried. You'll have some left over so get some stepping stone forms or other and use it all. So what if it doesn't work like normal concrete or last a hundred years. You've lost nothing but a little time, gained a lot of experience and it's disposed of and out of your way.


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## JustScrewIt

Ron6519 said:


> Such a cheap ass idea.


Yes. It is... But would it work?



Ron6519 said:


> Buy fresh concrete for the job


The bags I have were all bought within the last year and stored in dry place. So they're all relatively fresh. But, if you insist, I suppose I could sneak it on to the grocery list. We'll see if she falls for it...



Ron6519 said:


> and screw the planet.


That's already on the honeydon't list unfortunately.


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## JustScrewIt

SeniorSitizen said:


> Just mix it all together and you'll have some goooood stuff that no one has ever tried. You'll have some left over so get some stepping stone forms or other and use it all. So what if it doesn't work like normal concrete or last a hundred years. You've lost nothing but a little time, gained a lot of experience and it's disposed of and out of your way.


Exactly! Senior knows what I'm talking about! That's bcuz we both dare to go where no hack has gone before. And so, in the immortal words of Sarah Palin, I'm..."Going Rogue"! Thanks Senior for your guiding wisdom!

Huh. I guess it's true: Senior Sitizens, although slow and dangerous behind the wheel, can still serve a purpose! :biggrin2:


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## griz

Extending your walk 6" is going to be somewhat less than attractive anyways. That little dollop of concrete has good odds of coming apart no matter what you use.

Go ahead and use up all that old stuff.


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## JustScrewIt

Colbyt said:


> 15
> 20 +
> 10 +
> 15 +
> 10 +
> --------------------------
> 70 =
> 
> Does not even equal a single 80 pound bag. Skip lunch and buy a fresh bag, mix in a little of that Portland to increase the PSI.


I'll only need 60 lbs though won't I? I'm only doing a 1/2 cu.ft. I don't want to end up with extra again. That defeats the whole purpose!


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## joed

Portland cement is not concrete. You need to add sand and aggregate to it to get concrete.
Some of those are fast setting. That will probably make the whole batch set quickly. Be ready.

Mix it all together as one batch and pour it.


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## SeniorSitizen

JustScrewIt said:


> Exactly! Senior knows what I'm talking about! That's bcuz we both dare to go where no hack has gone before. And so, in the immortal words of Sarah Palin, I'm..."Going Rogue"! Thanks Senior for your guiding wisdom!
> 
> Huh. I guess it's true: Senior Sitizens, although slow and dangerous behind the wheel, can still serve a purpose!


Hey, cut the old man a little slack.:biggrin2:I drove 60 miles to town today 70+ MPH passing young whipper snappers with loud pipes. I forgot :vs_mad: half of what I went after but with the gas price down I can go back and get it tomorrow.:biggrin2:


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## JustScrewIt

griz said:


> Extending your walk 6" is going to be somewhat less than attractive anyways. That little dollop of concrete has good odds of coming apart no matter what you use.
> 
> Go ahead and use up all that old stuff.


I dunno, I've had good results so far when using that concrete bonder+fortifier stuff. I just add it straight out of the jug without water. The directions say to dilute it 1:1, but I haven't found any info that explains what will happens if I don't. I know that the cement needs water to hydrate and do it's thing, but the product already seems to be sufficiently watery as it is.


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## JustScrewIt

SeniorSitizen said:


> Hey, cut the old man a little slack.:biggrin2:I drove 60 miles to town today 70+ MPH passing young whipper snappers with loud pipes. I forgot :vs_mad: half of what I went after but with the gas price down I can go back and get it tomorrow.:biggrin2:


Don't you mean you WALKED 60 miles to town today? In the snow, uphill. Both ways...


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## Canarywood1

JustScrewIt said:


> I'll only need 60 lbs though won't I? I'm only doing a 1/2 cu.ft. I don't want to end up with extra again. That defeats the whole purpose!



A 1/2 a cubic foot weighs 75 lbs. so your lacking 5 lbs. wait until you have more left overs to tackle this job.


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## ront02769

To clarify a bit, roads and sidewalks and stuff aren't made of cement. They are made of a mixture of cement (which is mostly crushed limestone and silica) a and other aggregates. So you have one bag of cement....add sand in the right proportions and you end up with mortar mix (used to set block, bricks, etc). Add sand and some stone and you get concrete mix which yoiu pour to make sidewalks, roads, garage floors, foundations, etc.....all depending on the different aggregates, proportions of all ingredients, and other potential additives such as accelerators, binders, etc. just mix the cement plain with water, put it in a mold, let it cure, and whack it with a sledge and it will break into pieces.

The REST of your bags are mixtures of cement (as a binder) and various additives. All of THEM can be mixed with water and poured as a walkway, whatever. Mix THIS combo and pour it and whack it with a sledge and you will break your sledge before the slab gives. Ron


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## JustScrewIt

Thank you, Ron. Very informative and reassuring. 

Also, I am aware that Portland cement on its own has no structural strength but because the Sakrete Maximizer seems to have a surplus of aggregate (I've noticed it varies from bag to bag though) I figure adding the remaining 10 pounds of Portland cement would help to give it a smoother finish in the event I needed to use the Maximizer (which it sounds like I will, if for no other reason than because I won't have enough material to make the extension otherwise).

Really though I was just listing what I had available and seeing if there were any bags I could mix and match to get enough material to do the job. But I was thinking it would only require 50-60 lbs, not 75. Now I know I will need to use all the bags plus 5 pounds. So, I guess the question now is, if I'm able to drum up another 5 lbs worth of gravel and sand, will adding that provide me with a suitable proportion of aggregate-to-cement if I mixed all 5 bags together? Also, will rapid set cement and Portland cement combine together in the final pour without issue? By that I mean are the two cement types compatible?


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## Canarywood1

JustScrewIt said:


> Thank you, Ron. Very informative and reassuring.
> 
> Also, I am aware that Portland cement on its own has no structural strength but because the Sakrete Maximizer seems to have a surplus of aggregate (I've noticed it varies from bag to bag though) I figure adding the remaining 10 pounds of Portland cement would help to give it a smoother finish in the event I needed to use the Maximizer (which it sounds like I will, if for no other reason than because I won't have enough material to make the extension otherwise).
> 
> Really though I was just listing what I had available and seeing if there were any bags I could mix and match to get enough material to do the job. But I was thinking it would only require 50-60 lbs, not 75. Now I know I will need to use all the bags plus 5 pounds. So, I guess the question now is, if I'm able to drum up another 5 lbs worth of gravel and sand, will adding that provide me with a suitable proportion of aggregate-to-cement if I mixed all 6 bags together? Also, will rapid set cement and Portland cement combine together in the final pour without issue? By that I mean are the two cement types compatible?



The high early and the portland will definitely be compatible.


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## JustScrewIt

Thank you canary


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## Tscarborough

All of those are compatible. Just proportion the amount you have against the total amount used. That is, if you have 80# misc. and 800# of concrete required, then you would throw in about 10# per hundred of cement while mixing, if 400# concrete, then 20# per hundred..


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## Colbyt

10 of those pounds are pure Portland, you need about 5 pounds of crushed rock and 5 pounds of sand.


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## Mort

Here's what I would do. Mix them all together, place your concrete. If it turns out crappy, when you go to town buy a bag or two AND a sledge hammer.


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## JustScrewIt

what do you mean by "misc"? (besides 'miscellaneous'...)


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## JustScrewIt

Mort said:


> Here's what I would do. Mix them all together, place your concrete. If it turns out crappy, when you go to town buy a bag or two AND a sledge hammer.


If it turns out crappy, I want to know why it turned out crappy though. And I mean from a _scientific_ point of view! Dont you want to know why you do things one way and not the other? Besides, since my original question seeks to find out if mixing all these bags will produce a structurally sound block of concrete, if I need a sledgehammer to break it up, then it didn't turn out crappy. It turned out better than expected!


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## Tscarborough

If you want to know the science, see my sig.


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## JustScrewIt

Tscarborough said:


> If you want to know the science, see my sig.


classic!:vs_bananasplit::vs_rocking_banana: how'd you get :saddam: funny??

I'm still not sure I understand what you're talking about with the 80#/800# and 20#/400# thing though... Although it sounds pretty important so I wish I did. In any case, I already mixed and poured it and so far so good... will post update soon


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## Tscarborough

Try to keep the old stuff to less than 10% of the total used.


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