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would like to color concrete mix can I use outdoor latex paint to mix in with the concrete?

  • 10 Votes on the answer, but only one on the question? – MDMoore313 Mar 29 '15 at 0:19
  • This pinterest board says to replace 1/4 of the water with latex paint: pinterest.com/pin/311311392962557782 I have no idea if this affects the final resulting concrete. Would love an answer. – ssaltman May 26 '15 at 21:04
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While you probably could, this wouldn't be a good way to try and match a color. It would likely effect the setting performance of the concrete and you'd never match the color of the paint. On top of everything else, it would be much more expensive than the alternatives - all you really need is the pigment and everything else that makes up the paint is essentially wasted.

For coloring concrete it is much better to use products that are specifically designed for this - either a concrete dye mixed into the concrete itself, or a concrete stain applied afterwards.

  • This is actually not a very good answer. It is a supposition. I would like to know the answer to this question: will it have any noticeable affect on durability or strength of the resulting concrete? There is a pinterest board that says yes: pinterest.com/pin/311311392962557782 but I do not trust it. – ssaltman May 26 '15 at 21:02
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Cured concrete is a chemical brew. When concrete is setting, it doesn't just dry out. There is an exothermic chemical reaction going on. Go put your hand on it. It'll be warm (or hot, depending on how thick the pour is).

My point is that if you were to mix latex (rubber) into the concrete mix to color it, you would be interfering with the chemistry and would end up with weaker (or very weak) concrete.

The correct solution is a concrete dye or stain that is created for this purpose.

SERIOUS EDIT: A comment prompted me to do a little bit of research, and there's a chance that mixing the right proportion of latex paint into concrete based on Portland cement might be fine, or even improve certain properties of the concrete. Concrete curing absolutely is a chemical process, but it seems that the polymers in latex might actually work in a synergistic way with cement as both cure together.

It seems there has been substantial research in the past into PMC (Polymer Modified Concrete) or LMC (Latext Modified Concrete) to improve properties like tensile strength and chemical permeability. One of the problems was that the cost per gallon of LMC was three times as high as regular concrete. So there has been more recent research into the potential to use waste latex paint to produce LMC (Latex Modified Concrete). There's obviously more in latex pain than just latex and pigment, and it might differ quite a bit from brand to brand, but this is suddenly a pretty interesting possibility, to me.

A quote: "It is thought that a co-matrix is formed in LMC, where the cement paste is surrounded by a polymer film. Figure 1 displays a three step formation of the polymer-cement co-matrix (Ohama, 2005).

I haven't read the whole thing (skimmed it), and who knows if the link will last forever, but here's one resource from academia: http://digitalscholarship.unlv.edu/cgi/viewcontent.cgi?article=2232&context=thesesdissertations

Caveat Emptor. I'd do more research, ask more questions, and try to find specific information on what ratios to use, but this might be just fine to do!? ;-)

  • This answer, while suggesting a reason why it is not a good idea, also does not actually provide any experience or studies or examples to show whether mixing latext paint into concrete at certain unknown rations will have any affect on the resulting strength or durability of the concrete. – ssaltman May 26 '15 at 21:03
  • @ssaltman - While you have a point, remember that this is not a scientific nor engineering site. It is a DIY site, with insight provided by amateurs and professionals in the home improvement fields, none of whom are likely to have done thorough research on this particular experiment. – mbeckish Nov 15 '16 at 14:51
  • And my original point was that, hey, concrete doesn't just "dry." It's chemistry and the right answer is going to involve doing some research and/or asking a scientist or engineer, because concrete is chemistry, and dumping miscellaneous junk into the concrete may produce unexpected (unexpected by a non-chemist anyway) results. But having said that, it looks like dumping rubber paint into concrete might actually be a good thing. I'd still research it a little more. Or just try it and be ready to rent a jackhammer if it goes badly. :) – Craig Nov 15 '16 at 15:09
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I can tell you that I have mixed latex paint with Portland cement(Mortar mix). I put the slurry into a spray hopper and sprayed my concrete block wall. I wanted the wall to match the house in color and finish. It worked perfectly. I did this in 2008, and the wall looks as good today as the first day I sprayed it. The wall has an adobe finish, and the grout lines are not even visible. To this day there is not one crack, chip, or flaking going on. The wall finish is almost bulletproof!

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Why not just buy the pigments, buy the acrylic polymer, some sand and cement and start experimenting? I made concrete countertops this way with no previous experience. You'll have more control, and you'll be using ingredients that have been extensively tested and designed to work together.

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Isn't this the basis for products such as UGL waterproof paint? I know that paint MUST be added to ready mix drywall mud to accomplish water resistance prior to decorative finishing. I know acrylic additive is available for all portland cement based products. I know latex additive is available for ceramic tile mortars. In my estimation, these are over-priced dilutions. I have mixed paint with cement for decades and had very good results. "Bulletproof" (as the one comment said) is not an understatement!!

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