Pouring Concrete in Cold Weather – What You Need to Know
A lot of people wonder if you can pour and place concrete in freezing temperatures, especially with our harsh winters in Calgary. The quick answer is yes you can, but there are some things you need to know in order to have a successful pour. Which we will detail in this blog post.
Why you can pour concrete in cold weather
You can pour concrete in cold weather because the process of hydration and hardening of concrete is not affected by temperature. The ideal curing temperature for concrete is between 10 and 20 degrees Celsius (remember air temperatures may be different that the ground), however, concrete can be cured at lower temperatures as long as the concrete is protected from freezing. Additionally, the use of concrete admixtures, such as air-entraining agents and water-reducing agents, can help improve the workability and durability of your cold weather project. Calcium chloride and hot water are often used as an accelerator, to speed up the curing process.
What could go wrong when pouring concrete in cold weather
If concrete freezes during the curing process, it will result in a loss of strength and durability. Additionally, cracks may form in the concrete as it freezes and thaws. To avoid these issues, it is important to take precautions when pouring in cold weather which we will take a deep dive into below. The current American Concrete Institute (ACI) definition of cold-weather concreting, as stated in ACI 306 is, “a period when for more than three successive days the average daily air temperature drops below 40 degrees Fahrenheit and stays below 50 degrees Fahrenheit for more than one-half of any 24 hour period.”
What type of concrete mix to use
When cold weather concreting, it is important to use a fresh concrete mix that is designed for winter conditions. These mixes often have a lower water-to-cement ratio, which helps to reduce the risk of freezing and cracking. Additionally, they may contain admixtures that help improve workability and durability in cold weather conditions. It goes without saying that hot water should be used when mixing concrete in cold weather, as this will help to maintain a consistent temperature throughout the mix.
protect and insulate the area
When pouring fresh concrete in winter, it is important to insulate and protect the concrete surface area from the elements. This can be done by creating heated enclosures for the area with tarps or plastic sheeting, as well as using straw or hay to insulate the ground. Additionally, you will want to make sure that any exposed concrete is protected from the wind and frozen ground.
how to keep the concrete warm during and after the pour
There are a few things you can do to keep the concrete warm during and after the pour. Firstly, you can use insulating blankets or other means of heat source to keep the concrete warm. Secondly, you can pour the concrete into forms that are placed on top of a layer of insulation. Finally, you can cover the concrete with tarps or plastic sheeting after the pour to help keep the heat in.
Frequently asked questions about cold weather concreting
How long does it take for concrete to freeze?
Concrete can freeze within 24 hours if the temperature is below 0 degrees Celsius. However, the concrete will not be fully cured and will be susceptible to cracking and other damage.
Can you pour concrete in the rain?
Pouring concrete in the rain is not ideal, but it can be done if the proper precautions are taken. Firstly, you will need to use a concrete mix that is designed for cold weather conditions. Secondly, you will need to protect the area from the elements and keep the concrete warm during and after the pour.
Overall, it is possible to pour concrete in the coldest winters, but there are some things you need to know in order to have a successful pour. Firstly, you need to use a concrete mix that is designed for cold weather conditions. Secondly, you need to take measures to protect the area from the elements and keep the concrete warm during and after the pour. If you have any further questions, you can contact us and we will be glad to help.