Tools and Materials
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Steps for Using a Concrete Mixer
While mixing concrete by hand is good for small projects or concrete repairs, using a portable concrete mixer is best for large quantities of concrete. A concrete mixer or cement mixer uses a gas engine or electric motor to turn a drum or barrel to blend concrete mix and water into concrete. A concrete mixer is a good choice for projects like pouring a concrete pad or sidewalk.
We’ve got steps for using a portable electric concrete mixer to prepare ready-made, high-strength concrete mix, along with some tips for creating your own mix. Use the information as a general guide only. Follow the instructions for your material and your mixer.
A typical do-it-yourselfer doesn’t need to mix large amounts of concrete often enough to purchase a mixer, but you can rent mixers from some Lowe’s stores. Check the stores in your area to see if Lowe’s concrete mixer rentals are available near you.
Step 1: Plan Your Concrete Project
Use our Concrete Slabs Calculator or Concrete Footings Calculator to estimate how much concrete mix you need. Then check your mixer capacity. You need one cubic foot of mixer capacity for each 80-pound bag of concrete mix, so plan for multiple batches if necessary. You typically need to mix and use the concrete within an hour, so plan your timing as well, especially if you need to mix more than one batch.
While you can mix fast-setting concrete in a concrete mixer, mix only what you can pour and finish within 15 minutes. The mix begins to set in as little as 20 minutes and can become unusable for your project. Clean your mixer before the material hardens in the drum.
Step 2: Prepare to Work Safely
Follow the concrete, cement and mixer manufacturers’ instructions for use and safety. In general:
- Wear safety glasses, an N95 respirator and latex or nitrile gloves.
- Wear long sleeves, long pants and closed-toe boots or shoes.
- Avoid loose clothing and jewelry and tie back long hair.
- Work in a level outdoor area that’s clear of obstacles.
- Use a ground fault circuit interrupter (GFCI) outdoor outlet.
- If you use an extension cord, make sure it meets the specifications of the mixer manufacturer.
- Make sure the mixer is off and unplugged before moving or adjusting it.
Step 3: Prepare the Concrete Mixer and Material
Before you begin, check the mixer to ensure the fasteners are tight and the machine isn’t damaged. Make sure there is no debris or hardened concrete in the mixing drum. Secure the mixer to the ground, if recommended in the instructions, and lock the drum in place so it doesn’t tip.
Bagged Concrete Mix
Place the bags in easy reach of the mixer. Measure out the amount of water you need, according to the package instructions.
DIY Concrete Mix
To create a do-it-yourself concrete mix, you need Portland cement, sand and coarse gravel. The cement packaging should have instructions and ratios, but here are volume ratios for a general-purpose concrete mix:
- One part Portland cement
- Two parts sand
- Three parts gravel
- Water as needed
If you want to add color to your concrete mix, pour the colorant into the water before adding it to the mixer.
Step 4: Start and Load the Concrete Mixer
Plug the mixer in and turn it on. Make sure the drum is turning before adding any materials. Starting a machine after you load it strains the motor and can cause material to splash onto you. Don’t overload the mixer.
Bagged Concrete Mix
If you’re using pre-made concrete mix, pour 1/2 to 3/4 of the water into the drum and then add the mix. Let the material mix for about a minute and then add the remaining water.
DIY Concrete Mix
First add the gravel, then the cement, and finally the sand. Once the dry ingredients blend evenly, add water in small amounts until the mixture is workable.
Concrete mix is heavy. Enlist a helper to load the mixer.
Keep your hands and tools clear of the drum and mixer while the machine is running.
Step 5: Mix the Concrete
Allow the drum to mix the concrete for three to five minutes, until the mixture has the consistency of oatmeal. Add only a small amount of water, if necessary, to keep the material workable. Too much water weakens the concrete. Keep the mixer running while there is concrete in the drum.
Step 6: Pour the Concrete
With the mixer still running, unlock the drum to pour the concrete into the work area or a wheelbarrow. Double-check the consistency of the concrete. Make sure your gloves are on and take a handful of the mixture. You should be able to squeeze it together and it should hold together when you release it. If it crumbles, it’s too dry. If it doesn’t hold its shape, it’s too wet.
- If the mix is too dry, mix in a small amount of water.
- If the concrete is too wet, add small amounts of concrete mix or cement, sand and gravel.
Step 7: Clean the Concrete Mixer
Turn the mixer off and unplug it so you can clean it thoroughly. Clean the mixer as soon as possible to keep concrete from hardening in or on the machine. Make sure you’re wearing your eye protection, gloves and respirator. Follow the cleaning instructions for your mixer.
Typically, you’ll remove any remaining mix and then use a garden hose to clean out the drum. Dump the rinse water into a storage container, then rinse and dump again if necessary. Wipe off the exterior of the mixer and allow it to dry. Rinse, clean and dry the wheelbarrow and any tools you used.
Don’t pour the rinse water onto the ground or road or into a storm drain. Allow the water to evaporate and the remaining concrete mix to harden. Dispose of the material according to the procedures for construction debris disposal or recycling in your area.
Key Points for Using a Concrete Mixer
Mix large batches of concrete easily with a concrete mixer. Here’s what you need to know:
- Determine how much concrete mix and water you need.
- Follow the use and safety instructions in the manual and protect yourself with safety glasses, gloves and a respirator.
- Start the mixer and add 1/2 to 3/4 of the water, followed by the mix.
- Add the remaining water and then mix until the material has the consistency of oatmeal.
- Keep the machine running and pour out the mix.
- Clean the mixer and other equipment as soon as possible.
Shop Lowes.com to find all the tools and materials you need for your concrete project. Unless you mix concrete regularly, it’s a good idea to check our rental services to see if concrete mixer rentals are available in your area. Or stop by your local Lowe’s and talk to a Lowe’s Red Vest associate. They’ll let you know about available rentals and make sure you have everything you need for a successful project.
FAQ on Using a Concrete Mixer
Use the answers to these concrete mixing questions to plan your project.
How Many 80-lb Bags of Concrete Mix Can You Mix in a Mixer?
Generally, a concrete mixer can mix one 80-lb bag of concrete mix for every cubic foot of capacity. For example, a concrete mixer with a four-cubic-foot drum can mix four 80-pound bags. However, actual mixing capability depends on the mixer. Check the product instructions for specifics.
What’s the 1:2:3 Rule for Concrete?
The 1:2:3 rule for concrete gives a ratio of one part Portland cement, two parts sand and three parts gravel for creating a DIY general-purpose concrete mix. The cement packaging should list ratios for specific uses.
What Are Common Mistakes When Mixing Concrete?
- Adding the Wrong Amount of Water: Check the package instructions for the correct amount of water and pour in only small amounts of additional water as necessary.
- Not Mixing Enough: Estimate how much concrete you need so you won’t have to stop in the middle of your project and mix more.
- Undermixing the Concrete: Mix the concrete to the consistency of oatmeal, with no lumps of dry material.
- Waiting too Long After Mixing: Use the concrete within an hour of mixing it.
- Letting Concrete Dry on the Equipment: Clean the mixer, wheelbarrow and any tools you use as soon as possible after finishing your project.