Not all construction stops in the cold months of winter; much of it is a year-long industry, which means even concrete needs to be poured in the winter. Just because there are less than perfect weather conditions, the job must move forward. Now, that is not to say that there can be problems pouring concrete in the winter; there certainly can, but there are precautions to take, and the outcome will be extraordinary. But you need to realize that for a concrete project to turn out perfect, proper planning and execution are essential for a successful outcome. So if you are considering having a new concrete driveway or patio installed, but you are waiting until next spring because it is late in the season, you might want to rethink that strategy and have it done this fall or winter.
Possible Adverse Effects of Cold
Ice Crystals– Ice crystals can form in freshly poured concrete; if this happens and hydration stops, the impact will come in the form of lower-strength concrete. Should this happen, you could lose as much as half of the concrete strength. However, once the concrete reaches the strength of 500 psi, it can then endure one freezing cycle without being adversely affected.
Increased Set Times– Obviously, the colder the temperature when concrete is poured, the longer it will take to set correctly. For example, it will take concrete twice as long to set when it is 30 degrees outside than when it is 50 degrees.
Concrete Popsicle– Should outdoor temperatures fall below 25 degrees, you risk creating a concrete popsicle, which is basically frozen concrete. Again, should this happen, you can expect to lose a lot of concrete strength.
Expansion and Cracks– If the concrete is not adequately protected when it is poured in cold temperatures, there is a good chance the water in the concrete will freeze and expand, potentially causing cracks, which nobody wants.
Common Mistakes to Avoid
Never Allow Concrete to Freeze– This is quite critical, but you should never allow freshly poured concrete to freeze. Not only are you risking weaker concrete, but you could also develop cracks. It is best if you take full advantage of heating techniques that can be used to prevent freezing.
Frozen Ground– You should never pour concrete onto the frozen ground or on wet ground, snow, or ice. Placing concrete on frozen ground or ice will slow the setting time for the concrete and may complicate the process in other ways. In addition, frozen ground could settle once it has thawed, and this could lead to settlement cracks.
Cold Materials– It is imperative that you do your best to keep all of the materials from getting too cold. This means the mix should not be cold, the ground should not be cold, and the tools you use should not be too cold.
Tips When Pouring Concrete in Cold Weather
Before you even start pouring concrete in cold temperatures, you should have a plan of action that includes a definition of the strategies you will be using to ensure a successful pour. This includes keeping a chart of the temperature of the air and the temperature of the concrete. You should also schedule the pour for a specific time and keep a schedule of how you will protect the mix from the cold.
You need to determine the ways in which you are going to keep all of the materials from getting too cold. Devise a plan on how you will heat the water for the mix, how you will thaw the ground if necessary, and how you will keep the concrete from freezing once it is poured. You should also have a backup plan just in case something goes wrong with any of the equipment you are using to keep materials warm. For example, if you are using a heater to keep things warm, have a plan for what to do should that heater break down.
Protecting the Concrete
There are a few options when it comes to ways you can protect the concrete from freezing. Keep in mind that even in optimal conditions, concrete that is poured in cold temperatures will take longer to cure.
The first option, and probably the most expensive, is the use of a heated enclosure. There are many types of enclosures that can be utilized, including canvas tarps, pre-fab plastic enclosures, and wood enclosures. There are also several types of heaters that can be utilized to keep the concrete from freezing.
If the temperatures aren’t going to get below freezing, you can always use windbreaks to protect the concrete from biting winds. A windbreak of six feet is usually sufficient and will help protect the concrete as well as keep it from getting too cold.
There are accelerators you can use to hasten the curing time. But you have to be careful as these agents can corrode any rebar that might be used in the concrete slab, and it could lead to a mottled surface on colored concrete. There are some accelerators on the market that are very efficient and won’t discolor colored concrete; they are relatively expensive, though.
There are also insulating blankets available that can be used to help keep the concrete from freezing. Often, these are used in conjunction with other methods to keep concrete from freezing.
Making a Decision and Saving Money
Concrete can be successfully poured safely in the colder months of winter, but precautions must be taken. This means that homeowners who desire a concrete patio or other concrete project don’t have to wait until the warmer months of spring and summer when concrete contractors are super busy. Pouring concrete on cold days might seem like a difficult task, and it does come with a certain amount of risks, but as long as the contractor follows procedures and protects the project, everything will be just fine. And as a bonus, concrete projects in the cold winter months are less expensive, so you save money. In fact, you can save as much as 20 percent when you schedule your concrete project in the winter. Everybody likes to save money and this is a great way to get your project done in an affordable manner. If you have any questions about winter concrete projects, or if you would like an estimate for your winter concrete project, do not hesitate to contact us.