Written by Mike Day and published on https://www.everything-about-concrete.com/.
When most people think of concrete, they envision a hard, gray surface. However, concrete is actually a very versatile material that can be used to create a variety of different looks. The drying time for concrete depends on several factors, including the type of mix used, the weather conditions, and the thickness of the slab. In general, it takes about 24 hours for the concrete to cure enough to support light foot traffic. However, it can take up to 28 days for concrete to reach its full strength. For this reason, it’s important to be patient when working with concrete and to give it plenty of time to dry before putting any heavy weight on it. With a little bit of care and patience, you can create a strong, durable surface that will last for years to come.
How Long Does It Take For Concrete To Dry?
The correct term to use for concrete “drying” is curing. Concrete cures as it hardens and doesn’t dry.
After the concrete is poured in place, at 70° F, it typically takes about 8 hours for the concrete to cure enough to support foot traffic and not leave some type of footprint in the concrete.
Once the concrete is allowed to “dry” for 24 hours it will support normal foot traffic.
After 48 hours of cure time, you can start to build on it or begin to set heavier loads on the concrete.
Between 3 – 7 days of cure time you can drive on the concrete with smaller vehicles to larger trucks.
At 7 days of cure time, most concrete has reached about 70% of its full strength and sometimes even more.
At 28 days of cure time (or drying time) the concrete has reached full strength and is considered fully cured.
How Long Does It Take 4″ Of Concrete To Dry?
I pour and finish a lot of 4″ thick concrete floors, slabs, and patios. The time it takes for 4″ of concrete to dry (or cure) is really dependent on the temperature.
This garage floor took us about 30 minutes to pour and level. Then it took about 1 to 1.5 hours before we started finishing & troweling.
The troweling process took about 2 – 3 hours from start to finish. We started pouring at 7 am and finished power troweling at about 12 pm. It was 70° F when we started and 80° F at noon.
At normal temperatures (70 degrees F°) a garage floor like this will be hard enough to walk on in 8 hours. By “walk on” I mean you won’t leave a footprint but it will be easily scratched or damaged. It’s still what we call “really green”.
Most normal foot traffic can be done after 24 hours of cure time although 48 hours would be better.
In colder temperatures below 60 degrees F°, I would double the times above for use.
How Long Does It Take Concrete Driveways, Patio, and Pool Decks to Cure?
It takes between 24 – 48 hours for a broom-finished concrete driveway, patio, or pool deck to cure before you want to walk on it.
I would recommend waiting a full 48 hours before attempting to walk on new concrete that’s got a broom finish, 72 hours would be even safer.
The reason is the surface of broom-finished concrete is less dense than hard-troweled concrete. In other words, it’s “softer” and more likely to be damaged from foot traffic.
Giving the concrete 2 – 3 days to cure ensures the surface is hard enough to take foot traffic and not get scratched or gouged from shoes & boots walking on it.
I’d wait 7 days to drive on a new broom finished concrete driveway. The vehicle weight combined with turning tires could leave behind some damaged areas if you try driving on it sooner.
How Long Should Concrete Cure Before Putting Weight On It?
Concrete should cure a minimum of 24 hours before you put any weight on it. I’d keep the weight under 100 lbs. at this time frame.
Be careful though, the concrete has only reached a small fraction of its strength at 24 hours and could crack or break if too much weight is put on it.
You’re better off waiting 48 to 72 hours if you really need to put any type of weight on your new concrete. After 3 days of curing most concrete pours can withstand putting a small car on it. (it’s better to wait 7 days for cars and trucks if you can)
@ 7 days a 3000 psi. the concrete mix should reach about 2500 psi. strength
@ 28 days a 3000 psi. the concrete mix should reach 3000 psi. strength (or full strength)
How Long Does It Take For Concrete To Dry Enough To Walk On?
Walk on time will depend on what type of concrete mix you use and the outside temperatures. But in general, here’s the walk on times for some different types of concrete mix designs.
- Sakrete High Strength Concrete Mix – 24 hour walk on time
- Sakrete Fast Setting Concrete Mix – 6 hour walk on time
- Sakrete 5000 Plus Concrete Mix – 12 hour walk on time
- Quikrete High Strength Concrete MIx – 24 hour walk on time
- Quikrete Fast Setting Concrete Mix – 2 hour walk on time
- Quikrete Crack Resistant Concrete Mix – 24 hour walk on time
- Quikrete 5000 Concrete Mix – 12 hour walk on time
- Rapid Set Concrete Mix – 1 hour walk on time
All these concrete “walk on” times are based on using them in temperatures at 70° F.
If you’re asking the question Can I walk on concrete after 12 hours, the chart above will tell you which concrete mix you need to use in order to be able to do that?
How Can I Make Concrete Dry Faster?
If you need to “speed up” the set time of your concrete there are a few things you can do to make concrete dry faster.
- Use an accelerator additive – Sakrete has a non-chloride accelerator you add to concrete that will shorten set times and increase early compressive strength.
- Use calcium chloride – You can add some flake calcium chloride to a concrete mix and it will make the concrete dry faster. Adding a 50 lb. bag to 10 yards of concrete will shorten the set time by an hour or two. (depending on slump and outside temperatures) keep in mind CC could make your wire mesh or rebar corrode faster than normal.
- Use the correct amount (or a little less) of mixing water. Too much mixing water will increase the drying time.
- Use warm mixing water to speed up the drying time. Warm (or hot) water will speed up the “heat of hydration” and get you a faster setting concrete.
- Add heat and air movement to the space. Warming the air and adding a fan will help the concrete dry faster. If you’re concrete is inside a room, garage, basement, or building, add some heat and some fans to speed up the drying time.
How Long Does it Take For Concrete To Dry After It Rains?
The length of time it takes for concrete to dry after it gets rained on will depend on when it rains on it and how long it rains.
If it’s during the pouring process then this will increase the mixing water as the rain mixes with the fresh concrete. If it’s a short shower then the dry time may only take an extra hour or two than normal. If it rains for an hour or more then the dry time could take 2 – 6 hours long depending on the length of the rain storm.
If it rains after you get the concrete poured but the concrete is still very soft:
- A short rain storm 15 minutes or less – wait for the water to evaporate if you can or squeegee the surface when you can walk on it. Let the concrete surface dry as much as possible before finishing. Depending on temperatures and if the sun is out, this could take from 1 hour to 3 hours longer to dry.
- A long rain storm of 15 minutes to 1 or more hours – the concrete still sets up but the surface is very slimy and wet. Let as much water evaporate as you can but you may have to squeegee the water off when you can walk on it. Let the surface dry as long as possible before troweling. This could take 1, 2, 4, or more hours depending on outside conditions and length of rain storm.
If it rains after the concrete has just been broom finished you will need to cover it with some plastic to protect it. Then you may need to touch up the broom finish afterwards if the plastic causes some unsightly marks.
If it rains 2 to 4 hours or more after a broom finish the concrete should be hard enough to withstand the rain with no damage at 70° F.
If it rains after you complete a very smooth power trowel finish, the concrete should be hard enough at this point to not get damaged.
The length of time it takes for concrete to dry after it rains is different in every case. It depends on when it rains in the process, how long it rains, how hard it rains, is the concrete is covered or uncovered, does the rain damage the surface, there are so many factors to consider.
It’s best to never pour any type of concrete in the rain. Another tip is to never take a chance if rain is in the forecast. Concrete can get damaged and ruined if it gets rained on.
How Long Does It Take For Concrete To Dry For Fence Posts?
The drying time for a concrete fence post mix varies depending on the type of concrete mix you use.
- Sakrete Fence Post Concrete Mix – 12-hour set time (no mixing required for this mix)
- Sakrete Fast Setting Concrete Mix – 30-minute set time
- Quikrete Fast Setting Concrete Mix – 20 – 40 minutes set time (no mixing required)
- Quikrete Concrete Mix – 12-hour set time
The “no mix required” bags of concrete means you dig your hole, insert the fence post and brace it off, add the dry concrete mix around the post, and pour some water on top. Backfill and you’re done.
Refer to the manufactures data sheet for specific and more detailed instructions for use.
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