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Impact of Hot Weather on Concrete and Necessary Precautions

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Concrete placement should not be permitted if the ambient temperature exceeds 38°C to 40°C. hence, it is recommended to place concrete when temperature is less than 35°C. If the temperature reaches 35°C or more, special precautions must be taken, as hot weather accelerates water evaporation from the concrete. This rapid evaporation negatively affects the hydration process, leading to reduced concrete strength and durability.

Adverse Effects of Hot Weather on Concrete
  1. Increased Shrinkage – high temperatures cause excessive moisture loss, leading to greater shrinkage in concrete.
  2. Higher Risk of Cracking – Rapid drying can induce thermal and plastic shrinkage cracks.
  3. Reduced Durability – Increased evaporation increase concrete porosity, compromising its long-term strength and resistance to environmental factors.







Special Measures to Mitigate Hot Weather Effects

  1. To minimize the negative impact of hot weather on concrete, the following precautions should be implemented:Use Chilled Water or Ice – Mixing water should be cooled using chilled water or ice to reduce concrete temperature.
  2. Protect Aggregates – Aggregates should be covered properly to prevent heat absorption.
  3. Store Cement in a Shaded Area – Exposure to direct sunlight can increase cement temperature, affecting the mix.
  4. Pre-wet the Casting Area – Before pouring, sprinkle water on the formwork to prevent it from absorbing moisture from the concrete.
  5. Cover Reinforcement Steel – Reinforcement bars should be shielded from direct sunlight before concrete placement to prevent heat absorption.
  6. Minimize Time Between Casting and Curing – Immediate curing reduces excessive evaporation and ensures proper hydration.
  7. Erect Windbreakers in High Winds – In windy conditions, wind barriers should be installed to reduce evaporation and maintain uniform curing conditions.

By implementing these measures, the risks associated with hot weather concreting can be effectively minimized, ensuring better quality and durability of the structure.

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