Pouring concrete in freezing cold temperatures - yes, it can be done!
The new year symbolizes change for many, and so far this year, the US has received just that. A change in temperatures – record cold temperatures that our nation hasn’t experienced for years. The piercing cold blast sweeping through can slow down construction jobs; however, frigid temperatures don’t have to hold back building pros from using concrete.
Rest easy, a few preventative measures can be taken to ensure that chilly weather won’t weaken your concrete and slow down your job’s progression.
First and foremost – this might seem obvious, but we’ll go ahead and cover it for good measure – never pour on frozen ground. The warmer the ground, the better. If possible, suspend some tarps over the area and run a heater to raise the ground temperature, and make sure that forms and rebars are clear of snow and ice.
In cold weather, concrete can be batched with warm or hot water. Command Alkon’s automated batching solution, COMMANDbatch, offers a Precision Temperature System that measures the ingredient temperatures in a batch and adjusts water temperature to achieve a target concrete temperature for the load. This ensures that the concrete will be at the correct temperature when it comes time to pour.
After a pour, it is important that enough crystals form during the hydration process so that the concrete can resist destruction caused by rain and snow melt water that soaks in to the surface and freezes. The water added at the ready mix plant is needed to fuel the chemical hydration reaction, but avoid adding too much water to the mixture. COMMANDbatch also has a feature that can reduce the risk of adding an excessive amount of water to the load. The Post Load Process Manager feature automatically shows the driver what the target slump is, and the maximum water that can be added. This kind of intelligence can safeguard the quality of the load, and can strengthen the chance of the concrete properly undergoing the hydration process.
An excessive amount of water will keep the concrete saturated so that freezing will damage it even after it reaches compressive strength.
To ensure the workability of the concrete, COMMANDassurance provides a constant view of the properties of your concrete throughout the delivery cycle, and one of the features indicates how much water has been added to the load.
Finally, place triple layers of insulating blankets at corners and edges of the concrete that could freeze. Wrap any protruding rebars and make sure the blankets won't blow off during the night. If blankets alone can’t do the job, hydronic heating pipes or electric heating blankets can be used. These methods will keep the heat inside where it is needed so that proper hydration can take place, protecting your concrete from surface scaling, pop-outs, and cracking.
Bitter, wintry conditions can cause some major set-backs; don’t let it set your construction jobs back, costing you more time and more money.
Be knowledgeable; cold weather concreting brings special planning and special care. Concrete doesn’t necessarily like the cold, but if sufficient planning and care are taken, it’s possible to make it behave and cure to its proper strength.
Carter, T. T. (2015, February 26). Concrete In Cold Weather. Retrieved January 04, 2018, from https://www.askthebuilder.com/concrete-in-cold-weather/
Cold Weather Concrete- What happens to fresh concrete when it freezes? (n.d.). Retrieved January 04, 2018, from http://www.everything-about-concrete.com/cold-weather-concrete.html
Network, C. (2017, March 13). Cold Weather Concrete Placement- How to Protect and Cure Concrete in the Cold. Retrieved January 04, 2018, from https://www.concretenetwork.com/cold-weather-concrete/curing.html