5 tips and Precautions for Concreting in Cold Weather

The weather is one of the main concerns of concrete contractors. Indeed, this has a significant impact on the organization of external sites, thus forcing them to anticipate and adapt.

We are aware that the physical and mechanical properties of concrete can be greatly altered by extreme climatic conditions during construction.

As winter approaches, it's time to remind everyone of the few precautions and good preventive practices that allow you to continue building with complete peace of mind when the rigors of the cold strike.

The consequences of the cold on the concrete: beware danger!

Concreting in cold weather, when the temperature drops below 5°C, becomes more complex.

The cold penalizes the productivity of the site and slows down or even prevents the hydration reactions of the cement, thus the hardening time of the concrete is longer.

At a temperature below 0°C, the mixing water present in the fresh concrete freezes. This phenomenon generates the dilation of the water and together the increase in its volume (which can go up to 10%) creating strong pressures in the concrete and the formation of cracks.

Concrete Contractors Houston advice and tips for concreting in cold weather

Anticipate and adapt

If the weather forecast announces a drop in temperature and a risk of frost, it will be advisable as far as possible to limit the time for transporting the fresh concrete and waiting for the mixer truck on the site.

To limit its cooling, the concrete should ideally be worked as soon as it arrives on the site.

Monitor the ambient temperature and its evolution

After placing the concrete, it is essential in winter to maintain it for about a week at a temperature above 10°C in order to avoid any risk of thermal shock or cracking. This precaution will be necessary as soon as the thermometer drops or threatens to drop below 5°C.

Accelerate the hardening of concrete

Although cold slows the hardening of concrete, concreting in cold weather remains possible, as long as the temperature remains above 5°C. To do this, here are concrete contractors tips to prevent the effects of the cold on the quality of construction:

• Control the amount of mixing water by using a water-reducing plasticizer. 

• Use setting and hardening accelerating admixtures,

 • Prefer cements with a high heat of hydration 

• Increase mixing time. 

• Do not use frozen aggregates (Prohibition)

 • Keep the aggregates at a temperature above 5°C

 • Heat the mixing water

Limit the cold of the elements in contact with the concrete

Each element in contact with the concrete should ideally maintain a temperature greater than or equal to the freezing point, i.e. 2°C.

Finally, during the days following the placement of the concrete (about 3 days), it is important that the surface temperature remains above 5°C.

Protect and warm concrete

At temperatures close to 5°C, the concrete should be protected and warmed up. For this, it is possible:

• To use isothermal tarpaulins, 

• Use a heater 

• Heat the water up to a maximum of 70°C

In cold weather, the concrete will be all the more susceptible to defects or lack of cure. We remind you that the rules of the Art make the curing of the concrete mandatory.

All means are good to preserve the concrete from exposure to a temperature below 5°C!

Do not hesitate to consult Concrete contractors Houston before starting your project. Our experts are also at your disposal to support you at every stage of your project.

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