Pro Tip

Mixing Concrete Using a Mixer

 

Being confident in your project timing is the most important first step. Once you start mixing, you have approximately one hour to mix and place all of your materials to avoid cold joints.

With each round of mixing taking approximately 5 minutes, you can complete a maximum of 12 rounds of mixing in that timeframe.

Most standard mixers allow for a maximum of two 80# bags of concrete per batch for a total of 24 bags in an hour. Mixing flat-out, the output of this mixing method is capped at about 14 cu.ft. of material (or a roughly 6.5′ x 6.5′ x 4″ slab).

If you’re planning a larger pour, consider a second mixing station or dividing the project into smaller sections.

Project Tip: Use the Sakrete app to measure, estimate and purchase materials for the job straight from your phone.

Tools Needed

Mixing

Get ready to do some work!

  1. Measure the water according to the instructions on the bag. Water requirements vary slightly from mix to mix. Be precise!
    • Pro Tip: mark the water line on the bucket to make refills for successive batches faster.
  2. Pour about 3/4 of the pre-measured water into the mixer – this is called “head water”.
  3. Wearing gloves and respiratory protection, place bagged concrete mix on the edge of the mixer, cut open the open the top and pour into the mixer.
    • Pro Tip: To help control dust, cover the opening of the mixer with a trash can lid or other lightweight covering.
  4. Switch on the mixer.
  5. Mix for 3 minutes to thoroughly consolidate the mix and water, slowly adding the rest of the water along the way.
  6. Let the mix rest for 1 minute.
  7. Consolidate the mix by tapping the mixer drum with a rubber mallet.
  8. Check the consistency. A proper mix should hold together when formed into a ball but easily crumble with a light touch.
    • Concrete that is too wet will not hold together when packed into a ball – and will be weaker than the indicated strength.
    • Concrete that is too dry will pack into a ball but will “break” rather than “crumble” when touched and will be difficult to work and finish.
  9. Adjust water (if necessary) and mix for 1 additional minute to perfect the consistency.
  10. Transfer the mix from the mixer into a wheelbarrow or bucket to make transportation to the pouring site easier.
  11. Repeat!

Comments (6)

John Jay says:

Do you recommend skipping the 10 minute slake (rest) and remix? Is that no longer necessary?

Sakrete says:

John, 10 minutes is a bit long in our opinion. Honestly no reason to wait – once you’ve got a good consistency, you can get ‘er right in the forms.

Kevin McKnight says:

I have a question, I rented a 11 cubic feet mixer, how many 80 lb bags should I mix at one time. I have 75 bags to do

Sakrete says:

Kevin, one 80# bag is about 0.6 cubic feet, so you could TECHNICALLY fit 18 bags per batch. However, the weight is going to be your biggest consideration…that’s 1,400#!

For the sake of control, consider starting at around 6 bags per batch.

Jim McGahhey says:

I just wanted to say that this video gave me more information than all of YouTube! Thank you.

Sakrete says:

Glad we could help you out Jim!

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