Question

When pouring concrete in hot weather, which of the following conditions can occur?

1) Shrinkage cracks
2) Loss of strength
3) Fast hydration (stiff very quickly)
4) All of the above conditions

Answer 1

In hot weather, pouring concrete can result in shrinkage cracks, loss of strength, and fast hydration. All of the above conditions are correct, as they are manifestations of thermal stress which can lead to various structural issues in concrete.

Step-by-step explanation:

When pouring concrete in hot weather, the following conditions can occur due to thermal stress:

1. Shrinkage cracks - Concrete may crack as it loses moisture quickly and shrinks during the curing process in high temperatures.
2. Loss of strength - High temperatures can accelerate the hydration process, which can potentially lead to a weaker concrete structure over time.
3. Fast hydration - Concrete sets more rapidly in hot weather, which can make it stiffen very quickly and complicate the construction process.

Therefore, the correct answer is 4) All of the above conditions can occur when pouring concrete in hot weather.

These conditions are related to the concept of thermal stress, where materials expand and contract with temperature changes. Just as railroad tracks and roadways can buckle on hot days without sufficient expansion joints, concrete can exhibit similar issues such as cracking and compromised integrity under high temperatures. Such stresses can significantly impact the durability of concrete structures.