Pouring concrete in hot weather doesn’t have to end in disaster. It is possible to pour concrete in hot weather without suffering the consequences once your concrete cures.
Let’s take a few minutes to break down why hot weather affects concrete pours and what steps you can take to combat those affects.
What impacts your ability to pour concrete?
There are a handful of environmental conditions that can negatively impact your ability to pour concrete. Let’s take a look at some of the most common conditions.
Conditions that impact concrete projects:
- High ambient temperature
- High concrete temperature
- Low relative humidity
- Solar radiation
These environmental conditions can cause water to evaporate from the concrete surface. As a result, it becomes much more difficult to finish the concrete.
Said another way, the heat and sun suck the water out of the concrete mixture – which causes cracking and spalling. Afterwards, the concrete gets extremely dry and begins to peel, creating further issues.
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Can you pour concrete in hot weather?
Concrete can be poured in hot weather, but it’s important to plan ahead. In most cases, chemical methods can be utilized to combat the effects of hot temperatures on concrete mix.
Methods for controlling concrete in hot weather:
- Hydration stabilizers or shrinkage-reducing admixtures can be added to the mix.
- Some mid-range and high-range water reducers have a hydration stabilizer package that can control water loss experienced in the heat.
- Use ice and calculate the w/c ratio based on reducing the heat of concrete by a certain degree. There are equations available to help with this adjustment. To reduce the effect on the w/c ratio that is often seen with ice cubes, liquid nitrogen can be used to quickly reduce the temperature of concrete.
However, it isn’t always an option to plan ahead. This being said, if the hot weather is unexpected (or there are not enough people on the job site to help with cooling efforts), blanketing and tents can be used.
Higher-end versions of insulating blankets that are used to trap in water are available. These blankets can be wetted, used to reflect light, or both. There is also a hydronically cooled version, which keeps the temperature down and prevents water from evaporating.
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What problems can you run into when pouring concrete in heat?
There are a few major concerns that can happen when pouring concrete in the heat. These problems can all impact setting time and durability.
Hot weather concreting problems:
- You might experience a loss of water – which leads to cracking, spalling, and peeling
- The job will require more people (since you’ll need more hands to keep the concrete cool with blankets, sprayers, ice, topical admixtures, etc.)
- You may run into issues with the w/c ratio when adding ice/cool water
- The finishability can be affected with the reduction in water, and slabs are blessed or sprayed (which can impact the durability of the concrete)
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Our favorite tips for hot weather concreting
As we touched on earlier, there are a few ways to prepare for hot weather concreting. These methods can help you avoid the negative impact hot weather can have on pouring concrete.
Hot weather concreting tips:
- Add chemical admixtures to the mix to control concrete temperature
- Use liquid nitrogen to cool the concrete (without affecting the w/c ratio)
- Leverage hydronically cooled blankets to protect the concrete from water loss
- Time your pour and avoid the hotter part of the day
Want more guidance on concrete pouring hot weather?
We’d love to help! At Intelligent Concrete, we help companies with a variety of concrete solutions, including concrete testing, getting new technologies to market faster, and researching, documenting, and presenting concrete testing results.
If you have more questions, reach out to us online. We’d love to talk.
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