FIVE STAR REPLY!

You posed two questions:
(Q1) proportion of polymer vs water in paint may be lower than in the more
expensive admix

Answer:
cheap gloss latex paint is 20%+ polymer == please see numbers / sources in
previous post
Latex admixture is 4x% polymer.
Based on these numbers you get substantially more polymer/dollar with paint.
I am happy to hear that the polymers used in concrete admixtures are likely
the same as those used in paint.

(Q2) paint has pigments and viscosity modifiers that will likely weaken the
concrete.

Answer:
I am not aware that paint pigment weakens concrete (and I could always use
paint mixing base) but I am very happy you mentioned the viscosity
modifiers. They could be a deal killer and I will check them out right
away.

Thanks again,
William


"Richard J Kinch" wrote in message
. ..
William Deans writes:

Latex admixture for concrete costs many fold what cheap latex paint
costs ($4/gallon). What would happen if I just used latex paint
instead? Yes, I know it probably won't be as good as the special
purpose admixture-- but how far off are we talking about?

There are several items used both as concrete fortifiers and paint
polymers, including acrylics and PVA (polyvinyl acetate). PVA is also
what is in white glue or Elmer's glue. (Indeed, you can improvise your
own paint out of Elmer's and pigments).

PVA concrete admixes typically advise against immersion. Not as
resistant to water as acrylic.

The questions I would raise are (1) proportion of polymer vs water in
paint may be lower than in the more expensive admix, and (2) paint has
pigments and viscosity modifiers that will likely weaken the concrete.
So it is hard to tell whether you get more polymer per dollar in paint
vs admix.

(NB: "latex" in the context of paint or an admix has nothing to do with
rubber. It just means "emulsion", in this case of acrylic or PVA
monomers.)

As to whether it works, you can improvise scientific testing of concrete
for bonding and compressive strength with a shop press, if you are so
equipped.

If I had to guess, I would expect waste paint to improve concrete, but
not as much as a real admix.