How Long Should You Mix Concrete in a Mixer?

How long does a bag of concrete need to spin in the drum before it is ready? One manufacturer’s how-to page gives a range, but its own data sheet for the same mix prints no minutes at all. This guide separates what each document says.

Water First, Then the Dry Mix

QUIKRETE’s machine-mixing how-to page puts water in the drum before the dry mix. It names a barrel-type mixer and about 3 quarts of water for each 80 lb bag. The company’s dealer training module repeats the water-first order.

Here are the steps as that page words them:

1. Measure the water. Measure the recommended amount for the number of bags and pour half of it into the mixer.
2. Start the drum. Turn the mixer on and add the dry mix.
3. Wait about a minute. Then add the remaining water as necessary.
4. Mix about 3-5 minutes. Keep going until the mix is uniform and workable. Add small amounts of water sparingly when more is needed.
5. Empty the drum. Keep the mixer running and dump the concrete into a wheelbarrow.

The Concrete Mix 1101 data sheet (revised October 2022) agrees on the order. It says to add about 6 pt of fresh water per 80 lb bag to the mixer, turn the mixer on, then add the concrete. It prints no mixing minutes and no revolution count.

Batch counts are a separate question. The concrete mixer calculator turns a slab size into bags per batch and batches.

How Do You Know the Concrete Is Mixed?

QUIKRETE ties the end of mixing to a look, not only to a clock. The how-to page says properly mixed concrete looks like thick oatmeal and holds its shape when squeezed in a gloved hand.

The Concrete Mix 1101 data sheet adds a measured check for jobs with a slump cone. It says to adjust the water to reach a 2 in to 3 in slump (50 mm to 75 mm). It also gives a final water range of about 6 pt to 9 pt per 80 lb bag.

Hand mixing has its own test. The same data sheet says to work the mix with a shovel, rake or hoe, adding water as needed until it is stiff and moldable. It asks for no dry pockets of material and no standing puddles of water.

Penn State civil engineering course notes (undated, accessed 2026-10-19) make the same point from the engineering side. They say mixing time is not standard for each batch. It depends on the mixer’s type and condition, its speed, the size of the charge and the materials.

Why Do Printed Mixing Times Differ by Product?

Each product sheet prints its own instruction, and they do not match. The 3-5 minute figure comes from QUIKRETE’s how-to page and its dealer training module, not from the Concrete Mix 1101 data sheet.

The second clock matters on fast-setting products. QUIKRETE’s 1004-51 sheet gives a final set of 25 to 45 minutes and its 1004-50 sheet gives a set of 20 to 40 minutes. Each sheet also prints a placing limit, shown in the table.

How Long Would a Whole Slab Take in the Drum?

Drum time for the site tool’s 10 x 10 ft preset adds up to 93 to 155 minutes at QUIKRETE’s 3 to 5 minute range. That is arithmetic from the preset and the range, not a time any source gives.

1. Take the preset. A 10 x 10 ft slab, 4 in thick, with 10% waste, 80 lb bags and a 3.5 cu ft drum at 50 percent fill needs 62 bags. That is 2 bags per batch, so 62 / 2 = 31 batches.
2. Low end. 31 batches x 3 minutes = 93 minutes, which is 1 hour 33 minutes.
3. High end. 31 batches x 5 minutes = 155 minutes, which is 2 hours 35 minutes.

That is drum time before loading, emptying and placing. The tool page itself says only that a batch takes “several minutes” and gives no minute figure.

The two capacity rules also differ. QUIKRETE’s Concrete Mix 1101 data sheet says to allow at least 1 cu ft of mixer capacity for each 80 lb bag. That would allow 3 bags in a 3.5 cu ft drum. The tool’s usable-fill setting gives 2. Follow your own mixer and bag instructions.

For the volume side of the job, see the concrete volume and ordering calculators.

Extra Water, Long Mixing and Re-Tempering

More water makes weaker concrete, according to QUIKRETE’s how-to page. It says one extra quart of water per 80 lb bag can reduce strength by up to 40 percent.

Its dealer training module adds a timing limit: do not re-temper, which means adding extra water, after the concrete has begun to set. The module says re-tempering can cause excessive shrinkage and reduces the strength of the mix. For water per bag, see the water-cement ratio calculator.

The American Concrete Institute (ACI) covers mixing too long. Its FAQ says an excessively long period of mixing after adequate blending may be harmful in any type of mixer. Slump is reduced, and if water is added to restore the slump, strength is reduced.

That ACI text is general, not a bagged-mix rule. It also says long mixing of softer aggregates in a stationary mixer causes more slump loss. No manufacturer document read for this guide gives a strength loss from long mixing of a bagged mix.

What Do Ready-Mix Trucks Do, and What Do Sources Leave Out?

Trucks are counted in drum revolutions, not minutes. ACI says that with a proper loading sequence, truck mixers should adequately mix concrete in 70 to 100 revolutions. It puts the mixing speed generally near 12 to 18 rpm, within the range the mixer manufacturer recommends.

NRMCA CIP 26 covers water added at the jobsite. It says ASTM C94 requires another 30 revolutions at mixing speed after the water goes in. Ten can be enough if the truck mixes at 20 rpm or faster. This guide read that rule through the CIP, not the ASTM standard.

Here is what the sources read for this guide do not say:

• No universal minutes. No source gives one mixing time for every product.
• No time on some sheets. The Concrete Mix 1101 data sheet, the Fast-Setting 1004-50 sheet and the Canadian Sakrete sheet print none. Whether a US Sakrete bag differs is not verified.
• No overmixing number. No document read for this guide gives a strength loss for long mixing of a bagged mix.
• No ASTM C94 limits. The standard itself was not read, so its time and revolution limits are not stated here.

To compare a bagged job with a truck delivery, try the bagged vs ready-mix calculator or the concrete truck calculator.

FAQs About Mixing Concrete

Sources and Further Reading

The times here are printed figures from named documents, not a universal rule. Mixing times are product specific, so follow the instructions printed on your own bag. Reviewed for accuracy by Prof. Dr. Khalil Mudassar, PhD. Last updated 2026-10-19.