During cold weather, what is the minimum temperature difference required between surfaces in contact with fresh concrete and the concrete itself?

The correct answer indicates that a minimum temperature difference of 10°F is necessary between the surfaces in contact with fresh concrete and the concrete itself during cold weather conditions. This requirement is critical to ensure that the concrete can properly cure without being adversely affected by cold surfaces.

When fresh concrete comes into contact with colder surfaces, it can lead to a reduction in the curing temperature of the concrete. This can interfere with the hydration process, which is essential for the development of strength and durability in concrete. Proper temperature management is crucial in cold weather placements to avoid issues such as delayed setting times, increased likelihood of cracking, and inadequate strength development.

Maintaining a temperature difference of at least 10°F helps to ensure that the curing process proceeds as intended, promoting better bonding, reducing the risk of frost damage, and enhancing the overall performance of the concrete structure.