What is an effect of high ambient temperatures on poured concrete?

High ambient temperatures can significantly impact poured concrete, and one notable effect is the greater possibility of voids forming. When concrete is exposed to elevated temperatures, the water in the mix can evaporate more quickly than intended. This rapid evaporation may lead to inconsistent hydration of the cement particles, which can cause incomplete bonding and result in air pockets or voids throughout the concrete matrix.

The presence of these voids can compromise the integrity and durability of the concrete, leading to structural concerns. Moreover, high temperatures can cause the concrete to set too quickly, not allowing sufficient time for proper compaction and consolidation, further contributing to void formation.

In contrast, while slower curing rates, increased moisture retention, and decreased compressive strength can occur under certain conditions, they are not directly correlated with high ambient temperatures. Typically, high temperatures accelerate the curing process, potentially leading to challenges rather than slower rates. Moisture retention is generally better in cooler conditions, and compressive strength can vary depending on factors other than temperature, such as mix design and curing methods. Therefore, the possibility of voids is a direct consequence of the adverse effects of high temperatures on the curing process of concrete.