What measures are recommended for hot-weather concreting?

• A. Schedule during cooler times, use cold water and aggregates, windbreaks, and appropriate curing.
• B. Pour during hottest part of the day
• C. Use only warm aggregates
• D. No special measures are needed

Answer: (A)

In hot weather concreting, controlling temperature and moisture loss is essential. The goal is to keep the concrete cooler and prevent rapid evaporation so workability and curing aren’t compromised, which helps reduce plastic shrinkage cracking and thermal stresses.

Scheduling pours for cooler parts of the day reduces ambient heat impact and the rate of hydration. Using cold water and cooled aggregates lowers the initial concrete temperature, slowing hydration heat buildup and helping maintain a workable temperature range. Windbreaks or shading slow down air flow and reduce surface evaporation, keeping the mix and surface from drying too quickly. Proper curing, such as keeping the surface moist or applying suitable curing compounds, preserves moisture and stabilizes temperature during early hardening.

Pouring during the hottest part of the day would increase evaporation and thermal stress, making cracking more likely. Using only warm aggregates raises concrete temperature, defeating the purpose of cooling measures. No special measures ignores the problems caused by high temperatures.