Concrete cured with dark blotches

05.09.14
Had concrete poured in November and there are still some large, dark blotches on it. Need options for fixing them.
  • My concrete problem - walkway
  • My concrete problem - sitting area
  • My concrete problem - closeup. Notice the scratches on the dark area that show light greyy underneath, almost like the dark part is just on the surface.
  • Another closeup
on Mar 01, 2011
  • Paul Slayton Contracting
    Looking at the photos, this is definitely something you will have to get the contractor who did the patio out to remedy. You should have a one year warranty on materials and workmanship. Without seeing it in person, it is hard to say what is the cause,
  • Hudson Designs
    Hudson Designs Loganville, GA
    Looks like maybe rain got to the slab before it set and they topped the area that washed out maybe with Portland cement. Is that a leathery or wrinkled surface is see? There are different blends of Portland as well. Did you see them place it?
  • Brian
    Brian San Diego, CA
    Another closeup of my mystery concrete problem
  • Brian
    Brian San Diego, CA
    Just to wrap up: Turned out this was "retained moisture" caused by "hard troweling" where they trowled the surface a little too late, after it had already started to set up. This causes the top surface to "densify" which prevents all the moisture from
  • Nbt
    I have the same problem, but this is in a poured basement. Will the vinegar still work with no sun?
Brian

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