How to Use Ready Mix Concrete in the Winter
by TRP Ready Mix on November 30, 2017
Although Winter Isn’t Ideal for Concreting, If You Must Do It, Here’s What You Need to Know
Construction season in Ottawa is during the summer for a reason. The winter weather is often too unbearable to be working outside and isn’t a conducive environment for wet concrete. For most construction projects, the cold weather makes things more difficult. Pouring concrete is one of those projects that should be avoided during the winter. But if you must do it, it is possible. Here’s what you need to know.
As concrete hydrates with water, the hydration process creates heat. This heat can prevent concrete from freezing, cracking, and losing its strength in the winter. As the weather gets colder, ready mix concrete suppliers will use heated water and add accelerators to encourage fast and proper setting before the concrete freezes.
The Winter Mix
Concrete suppliers will heat the concrete during the mixing process at the concrete plant. This additional heat accounts for the inevitable drop in temperature during an average one-hour delivery in cold weather. Suppliers will also have heated water tanks to provide customers with the warmest concrete possible on-site.
The concrete mix also matters. Concrete suppliers will adjust the mix according to your project and the temperature outside. This helps concrete pour well and set quickly in cold conditions. Ready mix concrete prepared for winter use may include:
- Setting accelerators;
- Water-reducing additives;
- Avoiding the use of fly ash and slag cement—these set slowly and create less internal heat; and,
- Additional cement to generate more heat.
Adding accelerators to the concrete mix will speed up the concrete setting time, and allow the concrete to cure faster. This will also prevent the concrete from freezing and experiencing frost damage. Furthermore, accelerators will help speed up the finishing phase. The less time it takes to complete a concrete project from start to finish during cold weather, the better quality the finished product will be.
These additives create a higher-density cement paste which results in stronger, more weather-resistant qualities in the concrete.
Avoiding Fly Ash
If you plan to expose your concrete to de-icing chemicals once it has cured, then you will want to avoid or reduce the amount of fly ash added to the concrete mix. Fly ash can lead to the concrete’s surface peeling or scaling when exposed to de-icing chemicals.
Pouring Concrete in Cold Weather
Although the winter is not the ideal time to pour concrete, it is still possible to pour the concrete well enough to result in a strong, long-lasting finished product. To keep your poured concrete out of harm’s way in cold temperatures, remember these rules:
- You should never pour concrete on frozen ground, ice, or snow;
- If the ground is frozen, thaw it for two days using heat pipes and blankets/electric blankets;
- All corners and protrusions should be triple wrapped;
- Use a squeegee or vacuum to remove any standing bleed water if it doesn’t evaporate;
- Cover the concrete until it has cured—consider building a temporary shelter for it to keep it well-covered during cold, strong winter winds.
Keep these tips in mind if you’re planning a concrete project this winter. And remember, ready mix concrete suppliers are well-experienced in mixing and pouring concrete during any season, even in Ottawa’s harsh winters, so contact the pros for a quality winter mix and pour.