Tips for Pouring Concrete in Winter

When it comes to pouring concrete in winter, weather can pose significant challenges. Concrete sets best at 50-60°F; pouring concrete in winter means the ambient temperature will likely fall well below this range. Fortunately, there are steps you can take to effectively tackle cold weather concrete curing.

Concrete Pouring Temperature Limits

As mentioned above, concrete prefers a mild temperature between around 50 and 60°F to set. Below this, the exothermic reactions that cause wet cement to transform into strong concrete will slow significantly. This could mean long delays in work while you wait for concrete to set and strengthen before continuing with a project. Additionally, If concrete reaches freezing temperatures during the setting process, the water in the cement mix will freeze and expand. This will cause concrete to become weak, brittle and even flaky when it sets.

 

Successfully Pouring Concrete in Winter

Fortunately, strategies can be implemented to increase the temperature of cement mixtures. Here are some tricks you can use to keep the cement flowing all winter long:

  • Use heaters or heated blankets to thaw surfaces where concrete will be poured. Pouring concrete on frozen ground will quickly cool concrete well below ideal temperatures. Using a heater to prep surfaces will prevent too-quick cooling or freezing and help keep the necessary reactions going.
  • Mix cement using hot water to help increase the temperature of the concrete.
  • Store materials in a warm location.
  • Use quick-set cement; during cold weather. It may set more slowly than the instructions indicate, but will still harden more quickly than traditional cement mix.
  • Mix in additives that accelerate set time.
  • Use extra cement (typically 100 lb/ cubic yard) to make the reaction hotter and cause concrete to hydrate more rapidly.
  • Utilize squeegees or a vacuum to remove bleed water that has a difficult time evaporating during colder weather.

Cold Weather Concrete Curing

After the concrete has been poured, it needs to be kept at the correct temperature to cure. Most importantly, it needs to be kept from freezing. Ideal temperatures (50-60°F) should be maintained for about 48 hours for the concrete to reach optimal strength as it sets. This can be tricky during the winter; even if temperatures are optimal during the day, they can plummet at nighttime. Maintaining warmer temperature will require some sort of external heat source. One option is a heated enclosure. These are effective but can be time-consuming to install. If you choose to use an enclosure, be aware that excess carbon dioxide from the heater can cause bubbling in the surface of concrete. This can typically be avoided with proper ventilation.

Concrete Blankets

Another option for temperature maintenance during cold weather concrete setting is concrete blankets. Concrete blankets can be used to thaw ground before pouring concrete and again after finishing to keep concrete from freezing. They are easy to install and transport and require only an outlet to use. This means no time wasted setting up complex heating mechanisms. If you’re interested in minimizing downtime involved pouring concrete in winter, these blankets are an excellent heating option to look into.

How Cold is Too Cold to Pour Concrete?

What Temperature is Too Cold to Pour 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 required strength. However, if the correct measures are taken, concrete can still be successfully placed during even the coldest months of the year.

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 concrete has reached 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.

Powerblanket Concrete Blankets

Powerblanket® concrete blankets are an extremely effective option for attaining and maintaining the correct temperatures for concrete pouring and setting. Powerblanket® concrete blankets can be used to thaw ground before pouring concrete and again after finishing to keep concrete from freezing. Utilizing Powerblanket® concrete blankets will ensure that concrete is kept at the correct temperature for the necessary reactions to happen quickly and the desired strength to be reached.

What Temperature is Too Cold to Pour Concrete?

What Temperature is Too Cold to Pour Concrete?
What Temperature is Too Cold to Pour Concrete?

What Temperature is Too Cold to Pour 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 required strength. However, if the correct measures are taken, concrete can still be successfully placed during even the coldest months of the year.

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 concrete has reached desired strength to remove any framework. If the framework is removed too early, the concrete will be damaged and the surface could collapse.

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, allowing the concrete to eventually settle at 4000 psi. 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, not to mention a work hazard for employees.

Powerblanket® concrete blankets are an extremely effective option for attaining and maintaining the correct temperatures for concrete pouring and setting. Powerblanket® concrete blankets can be used to thaw ground before pouring concrete and again after finishing to keep concrete from freezing. Utilizing Powerblanket concrete blankets will ensure that concrete is kept at the correct temperature for the necessary reactions to happen quickly and the desired strength to be reached. With Powerblanket, it’s almost never too cold to pour concrete!

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Powerblanket Curing Blankets at the Statue of Liberty

Powerblanket® Goes to the Statue of Liberty

Reilly Construction out of Wrightstown, NJ won a bid from the U. S. Department of the Interior, National Parks to replace the roof of The Great Hall Statue of Liberty National Monument.  The Great Hall, which now houses the Ellis Island Immigration Museum, is considered one of the most symbolically important structures in American history. The Great Hall-Ellis Island was proclaimed a part of Statue of Liberty National Monument and is listed on the National Register of Historic Places.  Reilly nee
ded extra heat in the form of curing blankets to make this job happen.

 

The project involved removal of the existing inverted roof membrane assembly (IRMA) and replacement with a new multi-ply modified bitumen roofing system over a complicated tapered insulation deck assembly, approx. 60,000 Sq. Ft. The project also included the replacement of custom fabricated copper flashings and accessories throughout and the installation of a lighting protection system. Reilly worked with the NYS Historic Preservation Office (SHPO) to coordinate all the work.

 

Challenges Faced by Reilly

  •     Cold winter weather and high winds at this waterfront facility
  •     Working safely around thousands of tourists visiting this historic landmark daily
  •    Implementing various overhead protection plans at this historic landmark daily
  •    Mobilizing materials and equipment on a small island
  •    Limited laydown and staging areas
  •    Coordinating construction schedule with NPS & U.S. Park Police for VIP visits
  •    Ensuring compliance with the NYS Historic Preservation Office (SHPO)
  •    Day & night work


Finding Powerblanket

Dan DeSantis, the Senior Project Manager for Reilly, found Powerblanket products online and left his contact information. Upon follow up, we discovered that Reilly needed a heating solution to cure the masonry block work at the proper temperature (~50°F/~10°C) during December in New York and with the added chill of the water. Reilly used five Powerblanket MD0520 concrete curing blankets for the application, and appreciated the increased temperature control.

A Cure for What Ails You

Powerblanket concrete curing blankets provide a manageable way to cure concrete effectively and confidently in the cold weather months. Even in warm weather, Powerblanket curing blankets increase production by rapidly curing with consistent, even heat.

Why Choose Powerblanket Concrete Curing Blankets?

  •    Cure concrete 2.8 times faster than conventional, insulated blankets
  •    Produce cold weather concreting strength of up to 3,925 psi in 72 hours
  •    Maintain moisture throughout hydrating process
  •    Easily installed and removed
  •    Prevent a freeze cycle
  •    Thaw ground and frost from job site prior to pour
  •    Reduce downtime & increase profitability
  •    Maintain ACI compliance for cold weather concreting


Powerblanket at the World of Concrete—A Demo in Concrete Curing

Earlier this month, Powerblanket attended the 2015 edition of the World of Concrete at the Las Vegas Convention Center. This year’s exhibition attracted 55,779 registered professionals. In addition, the event drew in 1,459 companies exhibiting their products and services. For Powerblanket and its concrete curing demo, the event proved to be a great way to engage with those in need of the company’s products.

 

Powerblanket at the World of Concrete—A Demo in Concrete Curing

Powerblanket and the World of Concrete

For Powerblanket, this year’s World of Concrete was an exciting investment of company time and resources. Powerblanket ran a concrete curing demo to demonstrate the effectiveness of Powerblanket® curing blankets on the set times and structural integrity of concrete pours. Those who were present were able to witness for themselves how much efficiency the curing blankets added to the curing process. Not only were the blankets able to cure the concrete nearly three times as fast, but they were also able to increase the strength of the concrete by 50%.

The slab used for the demonstration was 8” thick with a mix design that was formulated to provide a minimal PSI of 4,000 in only two days.  The slab was poured two days prior to the demonstration, and for the purposes of the demonstration, one portion remained unheated while the other section was covered in an MD series Powerblanket® curing blanket. At the beginning of the demonstration, the unheated portion of the concrete measured close to the 4,000 PSI that was required for the minimal target. Then the Powerblanket was added, and the portion of the slab that was heated by the Powerblanket MD Series concrete curing blanket measured a consistent 6,000 PSI after only 16 hours in place. That’s a PSI strength increase of 50% over the unheated portion of the concrete slab.

Powerblanket® curing blankets allow for such efficiency through the company’s patented technological approach to concrete curing and many other heating solutions. Not only do Powerblanket® curing blankets insulate the chemical reactions responsible for concrete heat exchange, but they also add heat to the equation—making them far more efficient than the common curing blanket.  Through the Powerblanket design, electrical heat is evenly distributed through the entire application, allowing for quicker set times and stronger concrete.

“Seeing people’s reactions to the demonstration was exciting,” said Ryan Jensen, Marketing Director for Powerblanket. “It was clear that everyone was impressed with the outcome.”

As a result, Powerblanket has engaged with more customers in an industry they already heavily serve.

 

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A Concrete Curing Solution

If you live in the North American Mountain West, or any region where it gets cold during the winter months, chances are you’ve seen chipping concrete. Have you ever stopped to think what causes concrete to chip? Improper curing is what causes it, but with a good concrete curing blanket, this problem can be completely avoided.

 

A Concrete Curing Solution 1

Not All Concrete Curing Blankets Are The Same

If you’ve ever seen chipped concrete before, it’s likely due to cold weather. But we’re not talking about cold weather after the pour. No, chipping concrete often results from it being poured when it was too cold. This means the concrete never fully cured. Thus, it became brittle and flaky. The simple solution to this dilemma is either to wait until its warm enough outside, or else apply a concrete curing blanket.

If you did a search on Google for concrete curing blankets, you’re likely to find a myriad of options. But not all these options are the same. A good majority of the curing blankets out there are merely insulation blankets. Now insulation is a good thing to have in a curing solution, but it’s only half of the equation. The problem with simply insulating the concrete is twofold.

If you have a concrete blanket that only acts as an insulator then it’s not likely to help in the extreme weather. This is the first problem with an insulation blanket. The second is this: with only insulation on your side, you’re not going to be speeding up the curing process at all. When concrete cures, a chemical reaction occurs. This reaction causes the concrete to put off heat. With this in mind, placing an insulated blanket over the concrete will help to keep some of this heat in, but the amount of heat it will trap isn’t substantial enough to help cure concrete in really cold weather, or to speed up the curing process much either.

 

A Concrete Curing Solution 2

The Real Solution is Electric

This is why you need an electric curing blanket, or a heated curing blanket, to get the job done right. Electric curing blankets will both insulate and heat the concrete to an ideal temperature for curing. With the characteristics of a heated blanket at play, you can properly cure concrete in very cold temperatures. What’s more, even if the weather isn’t that bad, you can apply such a solution to speed up the curing process by leaps and bounds.

When it comes to picking the best electric curing blanket, there are a few major aspects to be concerned with. Number one, you want to make sure you get a blanket that will evenly distribute the heat throughout the entire application area. If the blanket is hotter in some places than others, you’re not going to get an even cure. Number two, you want to make sure you get a product that is properly certified for safety and efficiency. And number three, you want to make certain you purchase a blanket that can regulate its own heat. A blanket with a thermostatic controller will enable you to apply the heat and walk away without worrying whether it will keep consistent heat for the whole time you’re curing.

 

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The Wonders of Concrete: From Creativity to Concrete Curing

When most people think about concrete, their minds quickly turn to the common, grey, lifeless slabs that we walk and drive on. You can’t fault anyone for envisioning concrete in this way, but is it really a fair representation of such a versatile and varied construction material? We don’t think so. From creativity to curing, concrete is a truly amazing product.

 

The Wonders of Concrete- From Creativity to Concrete Curing 1

Concrete’s Real Potential

If you’re one of the individuals whose thoughts turn to sidewalks, interstates, overpasses, and patios when you hear the word concrete, well, it’s really to be expected. These forms of concrete application are certainly the most common. But there are also many other common uses that the typical person may not been clued in to.

Instead of settling on the usual image of concrete, take a chance to expand your horizon. Have you ever stopped to think about the many different types of pavement that exist? The fact of the matter is that much of the pavement you’ve seen, both indoor and outdoor, is some form of concrete. You see, concrete has possibilities for design that many people never even stop to consider.

 

The Wonders of Concrete- From Creativity to Concrete Curing 2

Decorative Concrete

For those in the know, concrete that falls outside of the stereotypical application and image is known as decorative concrete. And what some people have been able to do with decorative concrete is simply amazing.

Take for example the patterns that skilled concrete layers have been able to weave into what would otherwise be a very boring driveway. Perhaps you’ve seen the same techniques employed in outdoor walkways in and around historic downtown districts, malls, or river walks. Think of the innumerable possibilities that exist with such a method. Think of this, and you’ve only scratched the surface, though.

Even with as many outdoor uses concrete has, there are just as many indoor application methods. In fact, these types are the most stunning. Take a look at the picture below the driveway. Looks like tile; doesn’t it? Nope, it’s concrete, decorative concrete that has been designed to look like a very impressive tile pattern. Now take a look at the image below that. Looks like laminate wood flooring; doesn’t it? Actually, it’s concrete too.

This sort of thing is quite the surprise; isn’t it? For those who first venture into the realm of decorative concrete, the possibilities at first seem almost unbelievable. Oh, but they’re a very real and valuable way to make expanded use of one of the world’s most common construction products. To find more great examples of concrete usage, just type into Google: “decorative concrete” (under an images search).

 

Powerblanket and Concrete

If you’re in the concrete business, then you know how much freezing temperatures are an enemy to concrete curing. Well, whether you’re pouring concrete to create the usual, grey slab of strong and reliable stuff or your working concrete into a work of art, Powerblanket has you covered.

With Powerblanket® Concrete Curing Blankets, you can ensure the proper and ideal curing of concrete even in freezing conditions. You’ve never pour concrete in the cold? Well, how would you like your curing process to go nearly three times faster? In either occasion, Powerblanket can help.

 

Download Concrete Curing Test