Pouring Concrete in Cold Weather: How Cold is Too Cold?

ARTICLE AT-A-GLANCE

What is the Ideal Temperature for Pouring and Curing Concrete?

The optimal temperature range for pouring and curing concrete is between 50-60 °F, as temperatures below 50 °F slow the necessary chemical reactions, and below 40 °F, these reactions are almost non-existent, risking weak and inadequate concrete.

Key Takeaways

  • Understand Temperature Impact: Concrete’s chemical reactions slow below 50 °F and nearly stop below 40 °F, risking weak structures.
  • Optimal Pouring Conditions: Aim for 50-60 °F to ensure proper setting and strength development.
  • Cold Weather Strategies: Use heaters, hot water, and quick-setting products to manage cold conditions effectively.
  • Maintain Curing Temperature: Keep concrete above 50 °F for at least 48 hours using insulated blankets or heated enclosures.
  • Preventive Measures: Avoid freezing by thawing ground and using additives cautiously to accelerate set times without compromising integrity.

 Ground heating electrical blanket for curing concrete
Experts agree that the best temperature to pour concrete is between 50-60 °F. The necessary chemical reactions that set and strengthen concrete slow significantly below 50 °F and are almost non-existent below 40 °F. Even when daytime temperatures are within the satisfactory range, winter concrete setting creates risks that could result in weak, inadequate concrete. If nighttime temperatures are below freezing, the water in the concrete will freeze and expand, causing cracks. Additionally, if temperatures reach below 40 °F (but not freezing) during set time, concrete will take much longer to reach the required strength. However, if the correct measures are taken, concrete can still be successfully placed during even the coldest months of the year.

Protect your concrete pours this winter with a concrete insulation blanket. Our heavy-duty blankets provide the ideal concrete curing environment in cold temperatures.

Things to Consider with Cold Weather Concreting

Before embarking on a cold-weather concrete project, it’s important to determine any special strength requirements or considerations. This will help as you schedule your pouring and determine which strategies you will use to keep your surroundings and materials warm. The predominant challenge you will face during a winter concrete project is ensuring that the concrete sets before it is exposed to freezing temperatures. You might take the following suggestions into consideration as you plan your upcoming project:

  • Use heaters to thaw frozen ground, snow or ice.
  • Use hot water to mix cement.
  • Keep dry materials in a dry, warm location.
  • Use products designed to set quickly. During cold weather, these products will not set as quickly as the instructions may indicate but will set faster than conventional materials.
  • Use additives that accelerate set time. Use caution; if additives contain calcium chloride, any rebar or metal wire mesh in concrete will rust and cause concrete to crack.
  • Use extra cement (typically 100 lb/ cubic yard) to make the reaction hotter and cause concrete to hydrate more rapidly.
  • Remember that you still need to wait for bleed water to evaporate. Incorporating the water into the surface during finishing will weaken the surface. Bleeding starts later and takes longer during cold weather; you can use squeegees or a vacuum to remove water quickly.
  • Wait until the concrete has reached the desired strength to remove any framework. If the framework is removed too early, the concrete will be damaged and the surface could collapse.

Maintaining Ideal Temperature

After implementing the above suggestions, It’s important to consider how you will keep concrete at the correct temperature during the curing process. Concrete must maintain a temperature above 50 °F for approximately 48 hours for the correct chemical reactions to take place. Two popular options used during cold weather concrete curing are heated enclosures and insulated blankets. If using an enclosure, ensure that the structure is both wind and waterproof. Additionally, ensure that there is proper ventilation for the space heater. Heaters cause an increase in carbon dioxide that could cause carbonation in the surface of the concrete.

 

Frequently Asked Questions

How cold is too cold for pouring concrete?

Pouring concrete is too cold when temperatures drop below 40 °F, as the necessary chemical reactions slow significantly, risking weak and inadequate concrete.

What's the lowest temperature you can lay concrete at?

Concrete should not be laid if the air temperature is below 40 °F, and the ground or aggregate must not be frozen to ensure proper setting and strength.

Can you pour concrete if it freezes at night?

Concrete should not be poured if it is expected to freeze within 24 hours, as freezing can cause cracks and compromise the concrete's integrity.

What is the acceptable temperature for concrete?

The acceptable temperature range for concrete placement is typically between 50°F and 90°F, ensuring optimal chemical reactions and strength development.

Cure your concrete faster and better in cold weather conditions with Powerblanket.

Keep Your Project on Schedule with Concrete Blankets

Be Prepared For Winter Concreting

TITLE

Shelby Thompson

Shelby Thompson is the head of standard product sales for Powerblanket. He has a distinguished military career, having served in both Afghanistan and Iraq. In his time in the Marines, Shelby acquired an impressive skillset that he now uses in his current role. When he's not working, Shelby loves spending time outdoors with his wife, son, and daughter. He is also a semi-keen hunter, fair weather fisherman, and shooter. Unfortunately, Shelby also has something of an unlucky streak when it comes to Fantasy Football at the company.



Curing Cold Concrete: Electric vs. Insulated Blankets

ARTICLE AT-A-GLANCE

What Are Electrical Insulating Blankets and Why Are They Essential for Concrete Curing?

Electrical insulating blankets, such as Powerblanket’s electric concrete curing blankets, combine heavy-duty weatherproof insulation with electric heating components to maintain optimal curing temperatures between 65° and 85°F, ensuring faster and stronger concrete curing even in cold weather conditions.

Key Takeaways

  • Ensure Safety with Certified Insulating Blankets: Discover industrial-grade electrical insulating blankets that meet essential safety standards like OSHA and ASTM, providing reliable protection against electrical shocks and hazards.
  • Choose the Right Blanket for Your Needs: Explore a variety of options in sizes, voltage ratings, and materials designed for specific applications, such as live electrical work and arc flash protection.
  • Compare and Evaluate Suppliers: Gain insights into different suppliers, pricing, and product certifications to make informed decisions and purchase the ideal insulating blanket for your electrical safety requirements.
  • Optimize Concrete Curing in Cold Weather: Learn how Powerblanket’s electric concrete curing blankets combine insulation and heating to maintain optimal curing temperatures, ensuring faster and stronger concrete curing even in challenging conditions.
  • Prevent Costly Delays and Reworks: Understand the importance of using electric concrete blankets to avoid temperature-based defects, ensuring your construction projects stay on schedule and within budget.

Electric concrete blankets versus insulated blankets. Which one is best and why is it Powerblanket?

Not All Concrete Insulated Blankets Are Created Equal

If you happen to read almost any do-it-yourself guide, you will likely see a sentence that says, “If temperatures are below 40°F, use insulated blankets or straw to keep your freshly-poured concrete from freezing.” Well, that sounds nice and easy, but simply keeping concrete from freezing isn’t enough.

Why Heat Concrete?

The optimum range for proper concrete curing is between 65° – 85° F. When concrete dips below that range, ice crystals can form, cure strength will be compromised, and several temperature based defects can occur. Concrete pouring is a critical stage in any construction project and problems derail progress when it needs to be repaired or re-poured. Solely insulating concrete during curing seems appealing and money-saving, but can lead to costly time delays and expensive re-works.

What is Thermal Insulation?

Simply put, thermal insulation reduces the transfer of heat between objects. There are a myriad of both natural and synthetic materials used to insulate objects in different industries. When thermal insulation is placed on something that is already warm, it will prevent heat from escaping.

The chemical reaction of concrete formation is exothermic and does create some heat. This heat can be trapped (to some degree) with the use of insulating blankets or straw. But if it’s cold enough outside, insulating blankets won’t keep the temperature at an ideal level for maximum curing.

Insulation + Heating

When pouring concrete in cold weather, providing thermal insulation is only half the battle. Most insulated blankets will not provide enough surface contact to effectively insulate your concrete on really cold days. Combining the protective power of insulation plus even heat distribution gives you an advantage over mother nature.

Electric concrete heating blankets provide the protective layer of insulation and an extra boost of heating power to keep your concrete between 65° and 85° F. Concrete blankets have 10x more surface contact than other blankets. They efficiently transfer heat down into your concrete while heavy-duty weather-proof insulation protects it from the elements and heat-loss.

Thaw Before Your Pour

No insulating blanket on its own will thaw frozen ground, and pouring concrete on frozen ground can have serious repercussions.

electric ground thawing blankets

Electric ground thawing blankets are the best way to ensure your concrete pour gets off on the right foot. Using an electric ground thawing blanket prepares the ground before you pour so ambient temperatures above and below your concrete are at ideal levels.

Concrete Curing BlanketsMany factors have an effect on concrete cure time, such as the type of mix used, the size and shape of the slab, and the ambient weather. Of all these factors, weather and temperature is the most unpredictable. The colder the temperature, the longer concrete will take to set and reach its proper strength. During cold weather, a conventional insulated blanket will cause the concrete to take longer to cure and will result in a weaker concrete.

For example, concrete kept at 70°F will set in approximately 6 hours, whereas concrete kept at 40°F will take 14 hours to set. Concrete maintained at 70° F will reach a compression strength of 2,700 psi in 3 days; concrete maintained at 40° F will only reach a strength of 1,200 psi in 3 days.

This disparity in strengths makes a huge difference in whether your construction project can proceed. If concrete takes too long to set, cure, and strengthen, your project can be significantly delayed. Some concrete manufacturers find it too problematic to operate during the winter, creating a costly off season.

Concrete Solutions From Powerblanket

With Powerblanket, there is no off season. The difference between conventional insulating concrete blankets and electric concrete curing blankets is clear, and our electric blankets are a cut above the rest. By combining heavy weatherproof insulation with electric heating components, Powerblanket can cure concrete 2.8 x faster than conventional insulated blankets.

Our ground thawing blankets melt ice and snow and prepare the ground before your concrete is even poured. Our concrete curing blankets then maintain the temperatures you need to more quickly cure your slab to a strong finish. Powerblanket can eliminate costly weather delays, ensure your project proceeds on schedule and that your concrete will be long-lasting and durable. Contact us to find the right concrete solution for your needs 855.440.0208 or [email protected].

Frequently Asked Questions

Do insulation blankets work?

Yes, insulation blankets effectively provide temperature control and safety benefits, enhancing energy efficiency in industrial construction projects by maintaining optimal curing temperatures for concrete.

Are over electric blankets safe?

Yes, electric blankets designed for concrete curing are safe when used correctly, as they are engineered to maintain specific temperatures without posing health risks.

How do you keep electric blankets safe?

To ensure safety, always follow the manufacturer's instructions, avoid using them with incompatible materials, and ensure they are properly secured and monitored during use.

Cure your concrete faster and better in cold weather conditions with Powerblanket.


TITLE

Shelby Thompson

Shelby Thompson is the head of standard product sales for Powerblanket. He has a distinguished military career, having served in both Afghanistan and Iraq. In his time in the Marines, Shelby acquired an impressive skillset that he now uses in his current role. When he's not working, Shelby loves spending time outdoors with his wife, son, and daughter. He is also a semi-keen hunter, fair weather fisherman, and shooter. Unfortunately, Shelby also has something of an unlucky streak when it comes to Fantasy Football at the company.



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