DOWNLOAD: Concrete Mix Recipes PDF

     

    Mix design and recipe formulas are offered here by Expressions LTD as a reference. Expressions LTD is not liable for any results obtained by following mix designs outlined below. Mixes should be tested, and adjusted if desired, at each fabricator's discretion.  PSI rating for each mix is approximate, based on general data based on cements and additives, and their respective strength ranges.  Actual strengths of concrete are greatly affected by cement quality, sand/aggregate quality, water content used, etc. and cannot be pre-determined. Sample pieces should be made and tested using your locally sourced cement/sand/aggregates for strength verification, if needed.

    Make sure to check out our 40oz. Mixing Cups (sold here), very useful for all stages of mixing and dosing concrete, additives, and color- in addition to mixing the concrete sealers.


    Standard Expressions Concrete Countertop Mix: @6,000 psi

     Start with the basic bag mix: 60 lb. bag mix 80 lb. bag mix
    Coverage/Yield @ 1.5" Thickness 3.6 sq. ft. 4.8 sq. ft.
    Coverage/Yield @ 2" Thickness 2.7 sq. ft. 3.6 sq. ft.
    Add this stuff:
    Extra Portland Cement (Type I/II) 4 lbs. 5 lbs.
    Riteks Plasticizer/Water Reducer (sold here) 0.75 oz. (1.5 Tablespoons) 1 oz. (2 Tablespoons)
    Chopped AR Glass Fibers (sold here) 1.5 oz. (0.1 lbs) 2 oz. (0.125 lbs)
    Fiberglass Scrim Fabric* As needed As needed
    • Use the basic bag of standard concrete mix from your local hardware store (don't pay the extra for '5000' or 'Countertop' brand concrete mix).  You will also want to get extra straight Portland Type I/II cement from your hardware store.
    • *Fiberglass Scrim Fabric is generally placed in the middle of a concrete piece.  So the form filled 1/2 way, fabric laid in, and then concrete filled the rest of the form.
    • For the 80lb size batch: Combine concrete bag with extra portland cement.  Add about 3.5 quarts of clean water and begin mixing. Add small amounts of additional water** until concrete mix resembles that of very thick, dry oatmeal.  Now add in the Riteks Plasticizer, which should liquify the concrete mix.  Sprinkle Chopped AR Glass Fibers into mixing concrete and mix an extra few minutes. If additional water is needed, continue to add small amounts of water.  Final concrete mix should look and feel like oatmeal.  More water will make the mix flow better, but can compromise strength so keep it as dry as you can and still be workable for your need.
      • **Some applications may require a drier concrete mix (such as pressing very dry concrete into a form with the goal of creating large voids- to be filled later with a different colored cement slurry), or a wetter mix (filling a vessel sink 2-part sink mold), so adjust the water accordingly.

    Ultimate Expressions Concrete Countertop Mix:  @7,500 psi

    Start with the basic bag mix: 60 lb. bag mix 80 lb. bag mix
    Coverage/Yield @ 1.5" Thickness 3.6 sq. ft. 4.8 sq. ft.
    Coverage/Yield @ 2" Thickness 2.7 sq. ft. 3.6 sq. ft.
    Add this stuff:
    Extra Portland Cement (Type I/II)* 6 lbs. 8 lbs.
    Riteks Plasticizer/Water Reducer (sold here) 0.9 oz. (1.75 Tablespoons) 1.25 oz. (2.5 Tablespoons)
    Chopped AR Glass Fibers (sold here) 1.75 oz. (0.11 lbs) 2.25 oz. (0.14 lbs)

    Liquid Acrylic Polymer (sold here)

    OR

    Tec10 Dry Powder Acrylic Admix (sold here)

    @ 20 liquid oz

    -

    0.5 lbs

    @ 24 liquid oz

    -

    0.7 lbs

    Fiberglass Scrim Fabric* As needed As needed
    • Use the basic bag of standard concrete mix from your local hardware store (don't pay the extra for '5000' or 'Countertop' brand concrete mix).  You will also want to get extra straight Portland Type I/II cement from your hardware store.
    • *Fiberglass Scrim Fabric is generally placed in the middle of a concrete piece.  So the form filled 1/2 way, fabric laid in, and then concrete filled the rest of the form.
    • Combine concrete mix with extra Portland Cement*.
      • *Some may wish to add a pozzlan in place of some cement to claim the concrete is 'green' and has less of a carbon footprint.  VCAS (Vitro Minerals, sold here) can be added in place of up to 25% of the cement, which would mean adding 5 lbs. VCAS and 3 lbs. Portland Cement to the 60 lb. mix, or adding 6 lbs. VCAS and 4 lbs. Portland Cement to the 80 lb. mix)
    • For the 80lb size batch: Add concrete bag mix and extra portland cement to mixer.  In clean 5-gallon bucket, start with about 3 quarts of clean water, and mix in the Acrylic Polymer. Combine this mix water with the concrete, and begin mixing. Add small amounts of additional water** until concrete mix resembles that of very thick, dry oatmeal.  Now add in the Riteks Plasticizer, which should liquify the concrete mix.  Sprinkle Chopped AR Glass Fibers into mixing concrete and mix an extra few minutes. If additional water is needed, continue to add small amounts of water.  Final concrete mix should look and feel like oatmeal.  More water will make the mix flow better, but can compromise strength so keep it as dry as you can and still be workable for your need.
      • **Some applications may require a drier concrete mix (such as pressing very dry concrete into a form with the goal of creating large voids- to be filled later with a different colored cement slurry), or a wetter mix (filling a vessel sink 2-part sink mold), so adjust the water accordingly.

    From Scratch Countertop Mix: @6,000-7,500+ psi

    • 25 lbs. Portland Cement (Try to use Type I instead of Type I/II for pre-cast, but remember that Type I has higher strength, but a faster set time so you will need to work faster or have extra help!)
      • This recipe is good if you want to use White Portland Cement for your mix.
    • 60 lbs of sand/pea gravel. Make sure it's washed so there is no dirt or fine dust. It's okay for the sand to be damp when weighing it. A good starting point is 40 lbs. sand 20 lbs. pea gravel.
      • Consider using quartz sand (it's white) if using White Portland Cement, to help the concrete piece be as white as possible.
    • 2 oz. AR Glass Fibers (about a golf-ball sized portion) - SOLD HERE
    • 2 Tablespoons Riteks Superplasticizer/Water Reducer - SOLD HERE
    • MIX: Combine sand/gravel in mixer and let mix a few minutes. Add in Portland Cement.  In clean 5-gallon bucket, add about 2 quarts of clean water and 2 Tablespoons of Riteks Superplasticizer (and add the 2 lbs. of Acrylic Polymer if used). Combine mix water with concrete, and begin mixing. Add small amounts of additional water** until concrete mix resembles that of thick oatmeal. Sprinkle Chopped AR Glass Fibers into mixing concrete and mix an extra few minutes. 
      • **Some applications may require a drier concrete mix (such as pressing very dry concrete into a form with the goal of creating large voids- to be filled later with a different colored cement slurry), or a wetter mix (filling a vessel sink 2-part sink mold), so adjust the water accordingly.
    • Coverage: At 1.5" thickness, it will yield roughly 4.8 square feet. At 2" thickness, it will yield roughly 3.6 square feet.
    • Notes: Most Portland Cement bags are 94 lbs. Sand and Gravel can be purchased at a hardware store, already bagged, for a premium price. The more economical way to get sand/gravel is to get it from a gravel pit, or often times a concrete plant (the guys with the concrete trucks driving around) will let you come buy some very cheap, or give it to you at no cost for small amounts.

    Pourable SCC Sand-Only Countertop Mix: @6,000-9,000+ psi

    • SCC is for Self Consolidating Concrete.  Extra plasticizer is added to allow the mix to flow and fill in areas (self-leveling)
    • Coverage: At 1.5" thickness, one batch will yield roughly 3.9 square feet. 
      • Most sand mixes should not be used on anything thicker than 1.5". If you need the concrete to be thicker than 1.5" you should use one of the above regular 'concrete' recipes, that has pea gravel rock in it.
    • Use a 60lb bag of Sand/Topping Mix, from your local hardware store.  This bag has sand and portland cement already mixed (make sure you do not buy a bag of just sand!) 
      • You may choose to mix your own sand mix, especially if you want to use White Portland Cement.  The average starting point would be 20lbs cement and 40lbs sand.
    • Other Ingredients:
      • Mixing Process:
        • Tips about mixing:  Sand mixes typically work well to mix in a normal concrete drum style mixer, or by using a mixing drill in a 5-gallon bucket, but only if the mixing drill is powerful enough to do the job.  The Eibenstock Mixers we sell here are designed for this type of load. When it comes to using polymer, keeping the mix cold as possible will help reduce small pinholes in the finished concrete, so if possible add ice to buckets of water to chill it, and then use that cold water (not the ice though) in the steps below:
        • In a clean 5-gallon bucket add 2 quarts of clean COLD water, 6mm Fibers, Acrylic Polymer, and extra Portland Cement.  Blend with mixer for a few minutes until fibers are fully dispersed. 
        • Add 2 more quarts of cold water, and Plasticizer.  Then start mixing while adding the 60lb Sand/Topping mix to the bucket.  Mix for 1-2 more minutes, and then add 1 to 2 more quarts of water if needed to be a pourable, batter like consistency.
          • Some experienced fabricators may wish to add extra Superplasticizer to make the mix more flowable.  Please refer to the technical specs on the Riteks product on our site to calculate loading maximums for the plasticizer agent, and please note that the more plasticizer that is used, the more 'spongy' the concrete will become and it will take longer to fully set up hard.
          • You can make a note how much additional water you added to make the mix correct, and add closer to that amount at the beginning of the next batch to speed things up. Just make sure to not add too much water!
        • Please also consider that other reinforcements may be needed, such as Fiberglass Scrim Fabric (sold here) is always recommended!  And, often times a some 3/8" rebar in the forms.