A Quick Guide on How to Pour Concrete in Cold Weather

The worker pouring concrete
There’s no particular season for constructing concrete driveways, sidewalks, curbs and gutters or foundations; therefore, contractors can work on these projects throughout the year in hot and cold weather. While it is easier to pour concrete in warmer weather as the substances blend together faster, doing so in cooler temperatures requires additional steps to be taken by the contractor.

Many people, for this reason, leave the idea of doing anything with concrete during the colder months delaying safety hazards and necessary repairs that are needed. There are specific precautions which need to be taken while mixing concrete as the temperatures gets colder.

It’s not only possible, it's common to pour concrete during cold weather even though it comes with a few extra obstacles. Below are a few tips that aid contractors who undertake construction tasks during the Christmas holidays.

Concrete pouring process

Creating the Mixture

1. Proper Hydration

A chemical process called hydration is the first thing to do when pouring concrete in cold climate. The reaction takes place to ensure that the concrete being poured is hard enough. Chemically, the process involves mixing water with concrete that binds molecules of the two liquids together. The added accelerators further tighten the bond, thus hardening the concrete. It is an extremely important and sensitive process that can either solidify durability or break down the whole construction.

Hydration is generally a five-step process. It starts by mixing additional cement in the water and then adding hot water to the mixture. Later, the mixture is covered with curing blanket which accelerates the heating process. Finally, ethyl-based chemicals are added to speed up the process. Properly covering the mixture with the curing blanket is the simplest way of holding heat inside the concrete but must be done with care.

It is also important to ensure that the cement mixture doesn’t mix with the hot water directly. If this happens, it will create bubbles in the mixture that will become permanent if the same mixture is used for concrete. For this, a heating catalyst is mixed in the water making it suitable for cement.

2. Water-Cement Ratio

It is very important to take great care when mixing together water and cement. Any one substance poured more than required can case chemical imbalances in the mixture. This minor mistake can lead to permanent damage to the under-construction ramp or curb. The ratio of water to cement should not be more than 0.4.

3. Water Evaporation

While heating the water and cement mixture between 150 to 180 degrees Fahrenheit, it is important to let the water evaporate properly before going any further. Since the weather would be cold, it will delay the evaporation, so the person is advised to stay patient throughout this stage.

4. Pouring the Mixture

After the mixture has been prepared, it must be slowly poured while keeping the curing blanket intact. If the curing blanket is removed, it will cause a temperature discrepancy between the exterior and interior of the concrete. It must be ensured that the ground has been cleaned of snow or standing water.

Since the concrete needs to cure, forms and curing blankets are used to protect the newly poured concrete.

Worker is making concrete construction

After Pouring Concrete

Even after the mixture has been poured, there are certain guidelines which must be followed to ensure a faultless concrete pouring that can help in building a stronger foundation of the concrete curbs, steps or any other roadside construction.

1. Extra Precautions

After curing the concrete, it is recommended to check the efficiency of the insulation by measuring the concrete’s temperature. This can be done by inserting a thermometer between the concrete and the insulation to determine how successfully the insulating layer was placed. If the temperature is noticed to have dropped a few Fahrenheit, a material with a higher heating power like ethylene must be added to the mix to raise its temperature.

2. Constructing Heated Shelters

Under extreme cold conditions, which is rare in the Mid Atlantic region, a contractor could build a heated shelter for the poured area. Heated shelters are installed to provide proper ventilation for keeping the concerned area warm. Special care must also be taken to ensure that there’s no contact between the fresh concrete and any carbon dioxide-based materials, as calcium hydroxide present in the concrete would form dusting on the surface of the concrete upon reacting with carbon dioxide.

3. Time Taken

It is commonly suggested to maintain a temperature of 50-70 degrees Fahrenheit for the first couple of days. The temperatures are set to allow the cold concrete to gain maximum PSI.

A Few Common Mistakes

After discussing how to create, mix and pour concrete during cold weathers, it is also important to know about some of the most common mistakes contractors make. Some of these mistakes are:
      • Several handymen directly pour the concrete on a frozen ground. Frozen ground, when defrosting, can unsettle the concrete, causing it to crack.
      • Since its cold weather, chances are that the unused tools are also cold. Therefore, it is important to let them warm up before using them in the process. Cold tools can possibly modify concrete upon contact.
      • If fresh concrete is allowed to cure at a colder temperature, the process could eventually be stunted. Therefore, it is recommended to use curing blankets or portable heaters to provide the proper heat. Also, remain cautious as excessive heating can weaken the concrete sidewalks or ramps.
Even though the process of pouring concrete during cold weather may seem intimidating, by following proper guidelines and taking accurate precautions, you can have all of your tripping hazards and repairs completed during the winter months.

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