Hot Weather Concrete Construction Practices

Why are Hot Weather Concrete Practices and Precautions so Important?

  • Weather plays a major role in concrete construction due to the chemical reaction known as hydration. When new concrete is placed on a hot day with low relative humidity, hydration is going to happen much faster due to evaporation of the water from the surface of the concrete. In order to properly finish a concrete slab on a hot day, we need to understand what exactly hot weather concreting is and the methods to working in hot weather.

What Specifically is Hot Weather Concreting?

Hot weather concreting is classified by any combination of the following conditions:

  • High Outside Temperatures
  • Low Humidity
  • High Concrete Temperatures
  • High Wind Speeds

Hot Weather Concrete Temperature Requirements:

  • The maximum allowable fresh concrete temperature is 95 °F. If a concrete truck sits too long on a hot day, this temperature can easily be exceeded within an hour.
  • Protection of the concrete against drops in temperature of more than 40 °F in the first 24 hours.

What Methods Aid Pouring Concrete in Hot Weather?

  • Pre-pour Meeting
  • Initial Curing: Fogging & Evaporation Retarders
  • Water Reducing Admixtures
  • Cold Water / Ice
  • Reduce Time of Transportation, Placing, & Finishing
  • Early Morning or Night Pours