Concreting in Freezing Temperatures: Safe Winter Concreting Guidelines

Many contractors wonder whether it is possible to pour concrete at temperatures of –5, –10 or even –15 °C. The answer is yes, but only if the correct anti-freeze admixtures are selected and the technology is followed strictly.

Why Frost Is Dangerous

At low temperatures, water in concrete freezes, stopping the cement hydration process. As a result, the concrete:

• does not achieve sufficient strength
• becomes brittle
• may lose density and crack resistance
  
  

Rules for Safe Concreting

1. Minimum cement content: 270–300 kg per 1 m³.
   
   
2. Do not use frozen aggregates.
   
   
3. Use heated water; the temperature of the prepared mix should be ≥ 10 °C.
   
   
4. Thoroughly remove snow and ice from formwork, reinforcement and shuttering.
   
   
5. At temperatures < –5 °C, freshly placed concrete must be protected with insulation or heated using electric curing methods.
   
   

Optimal Concreting Conditions with Admixtures

• up to –5 °C — minimum admixture dosage;
• up to –10 °C — increased dosage and insulation required;
• up to –15 °C — only chloride-free anti-freeze admixtures should be used, together with strict temperature control of the mix.
  
  

Anti-freeze admixtures allow concrete to set even in severe frost, reduce water demand and increase strength.

For a detailed explanation of how these admixtures work, read our article on winter concreting.

Conclusion:

Concreting in freezing temperatures without special precautions is risky. Following the correct procedures and using anti-freeze admixtures helps ensure safe and high-quality results.