After knowing the expected weather conditions on-site, the concrete mix design can help to reduce the associated risks with hot-weather concreting:

Reduce the Cement Content
When designing a concrete mix for hot weather concreting it is recommended to reduce the use of cement, within a reasonable margin, while still satisfying the strength and durability requirements. This will reduce the heat emission and slow down the rate of cement hydration as well as minimize the thermal expansion and the risk of cracks. An additional benefit of reducing the cement content is lower CO2 emissions for the concrete mix used, for a more eco friendly construction project.

Add Admixtures
Some admixtures, such as fly ash or GGBS (Ground Granulated Blast-furnace Slag), may be used to delay the setting time and reduce the heat emission from the cement hydration process.

Reduce Concrete Temperature
One of the most successful techniques in warm weather is to reduce the temperature of the concrete mix by cooling it down. This can be done in multiple ways, and ACI recommends the following techniques:

  • Cooling the concrete with chilled mixing water
  • Cooling the concrete with ice
  • Cooling the concrete with liquid nitrogen
  • Cooling the concrete aggregates

These techniques have the potential to reduce the concrete’s temperature by 0,5 °C to 11 °C depending on the chosen technique. It is worth noting that the cost of the different techniques presented above differ considerably depending on the required equipment, personnel expertise, project location, etc.

Minimize Transport Time
It is important to minimize the transportation time as much as possible and reduce the risk of delays to prevent early concrete setting problems. These could range from the concrete mix hardening in the mixing truck to the added difficulty of pumping the concrete due to high rigidity.