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I am looking for advice on how to smooth out the surface of my newly done concrete slab. I used 2x6 studs to make a raised slab for a concrete fountain that will be placed in the center. Only about 10" of a ledge all around my newly constructed slab will be visible as well as a portion of the sides. Sadly, I did a pretty lousy job at making a nice smooth modern looking finish. I was having an extremely difficult time leveling the surface and unable to smooth out all the aggregate. It sort of looks like spalling in some areas. I don't know what I did wrong. But due to not being able to rent a large barrel concrete mixer I had to mix twenty-two 60lb bags by hand which really wiped me out. I was exhausted by the time it came to smoothing everything out. I made two of these slabs (11 bags per slab). Here is a photo of what I'm trying to improve:

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I'll be taking off the form this evening which will have been a full 24 hours.

Can someone recommend the type of product I can use to smooth this out so that it looks a lot better? I am pretty sure that cosmetically I will be happy so long as someone can recommend the right product. Something that I can smooth over with an extra wide putty knife just to smooth out the surface? Lastly, i'm going to paint the concrete with Deckover to match the sidewalk in the same area. Deckover is really remarkable in smoothing out a surface and hiding imperfections. My thirty year old sidewalk looks brand new.

Would I use a vinyl concrete leveler or some type of stucco product?

Lastly, can I do this ASAP or do I have to let the concrete slab cure for a certain amount of time first? Due to time constraints I'm hoping to do this as quickly as possible.

Looking forward to some suggestions.

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If the entire slab is not well finished, you should consider hiring a professional finisher to add another layer of cement-rich mortar. The result will be much better if performed as early as you can - before the concrete has dried significantly, or keep the slab moist/wet.

For small deficiencies, fill the honeycombs with a stiffer mortar (non-flowable) by rubbing and pressing by hand (with the protection of a heavy-duty glove), Then scuff the sand-cement mortar with a pole sander or a hand sander. For larger jobs, rent a floor sander. Mix a few drops of dish detergent into a bucket of warm water. Mop the surface of the concrete floor with soapy water to remove any dirt and grease deposits. Rinse the floor with clean water and allow it to dry. You may repeat the process to get the desirable result.

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  • Good catch. Thanks.
    – r13
    Nov 4, 2021 at 19:29
  • I am looking at products available for me to pick up so I can do this tonight. Would a vinyl based concrete patcher work or should I stick to mortar based? I am guessing that this 40lb bag would take care of both of my raised slabs: homedepot.com/p/…
    – Adrien
    Nov 4, 2021 at 22:19
  • I am not familiar with the vinyl-based concrete patch. By reading the instruction, it seems a self-adhering, strong compound for repairing cracks by applying a thin coat, but its quick drying property worries me as you might end up with a lot of overlappings that require additional smoothing. I would try out on a small area to make the decision.
    – r13
    Nov 4, 2021 at 23:15
  • @Adrien "so I can do this tonight." - negative. The only thing you're supposed to be doing to a fresh pour is keeping it wet for the next 28 days. If the paint product says "fully cured" that's one month.
    – Mazura
    Nov 5, 2021 at 19:54
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    "Remove all unsound concrete from the area to be repaired. Wear proper personal protective equipment. Using the tip of a trowel, pry up any loose pieces of flaking or cracked concrete. Vigorously remove any crumbling concrete with a wire brush. Smooth surfaces must be roughened. Do not apply over painted surfaces. Using a brush, remove all loose particles and dust from the area to be patched. Clean the area with QUIKRETE Concrete and Asphalt Cleaner (No. 8601), then rinse with water."
    – Mazura
    Nov 6, 2021 at 20:30

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