Concrete Slurry

CX Pro-Formula Acrylic Slurry is a quick and easy way to fill holes in a concrete countertop that appear after polishing or after releasing concrete from the mold. With a “gel-like” consistency, this fast-acting slurry can also be used to fill voids and make repairs on vertical surfaces.

Slurry is a mixture of cement paste, pigment, and water. It is used to fill in the small air bubbles on the surface of the concrete. This is especially important in something like a concrete countertop, because bacteria can get into those holes and grow. Otherwise, it’s an aesthetic preference; some people don’t mind the natural look, while others are looking for a more refined surface.

Acrylic slurries are available and have the advantage that they will shrink less and adhere to the vertical surfaces better.

Polishing the piece will open up more holes in the surface, so filling the holes with slurry should happen between the final stages of polishing.

What You’ll Need

Step 1 – Polish surface if desired

Using Acrylic Concrete Slurry - Step 1 | Concrete Exchange
  • Before mixing the Acrylic Slurry, polish the countertop to the desired depth. A minimum of 400-grit finished surface is recommended before slurrying. Check out the Polishing Concrete Guide for more information.
  • The countertop should be damp with water before applying slurry. It should not be dry, but there should be no standing water on the surface either.
  • For a Cast Finish (un-polished):

    •     Seal the piece first to avoid staining it with slurry.
    •     Spot-fill the voids with slurry using the methods that follow.

Step 2 – Mix Slurry

  • Place the Pro-Formula Acrylic Slurry into a mixing container.
  • In a separate container, measure out 6 ounces (175mL) of water.
  • Slowly add the water to the dry ingredients. Add only enough water to create a toothpaste-like consistency. You will need approximately 6 ounces (175mL) of water for a whole bag of slurry, depending on color.

Step 3 – Apply Slurry

  • Wearing rubber gloves, place a handful of slurry on the countertop and work in circular motions, ensuring that all small holes and voids are filled.
  • Using a plastic putty knife, scrape off the excess.
  • Leave the holes over-filled because the slurry will shrink as it dries.

Step 4 -Wait for it to Cure

Using Concrete Acrylic Slurry - Step 4 | Concrete Exchange
  • Let the Acrylic Slurry cure for 1 day.

Step 5 – Wipe Up Slurry

Using Concrete Acrylic Slurry - Step 5 | Concrete Exchange
  • Lightly polish the surface starting with a minimum 400-grit polishing pad, concentrating on removing the dried paste from the surface.
  • If the slurry has shrunk back into the holes, repeat the process. Two coats are usually sufficient to fill the holes.