Red Seal Concrete Finisher Practice Exam

How does temperature affect the curing of concrete?

1. Hot temperatures slow down the curing process

2. Cold temperatures cause faster evaporation

3. Hot temperatures can cause faster evaporation and set time

4. Temperature has no effect on curing

The correct answer is: Hot temperatures can cause faster evaporation and set time

The choice that highlights how temperature affects the curing of concrete correctly identifies that hot temperatures can lead to faster evaporation and a quicker set time. When temperatures rise, the rate of evaporation from the surface of the concrete increases. This can lead to surface drying before the concrete has had a chance to properly hydrate, which is crucial for developing the desired strength and durability. Additionally, higher temperatures accelerate the chemical reactions involved in the curing process, causing the concrete to set more quickly. This can result in challenges such as "cold joints," where new concrete does not bond well with the existing material due to premature curing. Conversely, lower temperatures typically slow down both the curing process and the hydration reactions, which can extend the time it takes for concrete to set and ultimately achieve its strength. While cold temperatures are indeed associated with slower curing, they do not cause faster evaporation; in fact, the risk of evaporation usually decreases in cooler conditions. Overall, understanding the effects of temperature on concrete curing is essential for ensuring that proper measures are taken during the mixing, pouring, and finishing processes to achieve optimal results.