North Carolina Building Contractor License Practice Exam

Which of the following is not included in the requirements for concrete subject to exposure?

1. Use of additives

2. Minimum curing temperature

3. Moist maintenance

4. Minimum strength testing

The correct answer is: Use of additives

The focus of the question is understanding the specific requirements that concrete must meet when exposed to different environmental conditions. When dealing with concrete that will be subject to exposure, several established criteria must be met to ensure its durability and performance. The option regarding the use of additives refers to materials such as accelerators, retarders, and water-reducing agents that can modify the properties of concrete. While additives can enhance certain characteristics of concrete under exposure conditions, they are not a requisite stipulation for all concrete exposed to environmental elements. In contrast, the other requirements—minimum curing temperature, moisture maintenance, and minimum strength testing—are crucial for ensuring that the concrete achieves the intended durability and performance objectives, particularly in adverse climates or severe conditions. The minimum curing temperature ensures that the hydration process of the cement occurs effectively, preventing premature freezing or inadequate strength development. Moist maintenance relates to keeping the concrete hydrated during the curing period to avoid cracking and ensure proper strength gain. Finally, minimum strength testing serves as a standard measure to confirm that the concrete performs adequately for its intended use. Thus, while the use of additives can be beneficial, it is not a mandatory requirement that must be met for concrete that is subject to exposure.