Published on Civil + Structural Engineer in October 2020.
Placing concrete in hot weather necessitates extra precautions to ensure that the concrete sets properly and gains strength at a stable rate. Hot weather accelerates early-age strength gain, which can be an advantage in construction, but temperatures that are too high could cause concrete durability problems such as delayed ettringite formation (DEF) or drying shrinkage.
Therefore, regulating the temperature of concrete in hot weather is essential to its proper strength development. The American Concrete Institute (ACI) specifies in ACI 305R-10 Guide to Hot Weather Concreting recommended maximum concrete temperatures both at delivery and during curing. These recommendations are often mirrored as requirements in job specifications.
