North Carolina Building Contractor License Practice Exam

How is slump affected by temperature?

1. The higher the temperature, the higher the slump

2. The higher the temperature, the lower the slump

3. The temperature does not affect slump

4. The lower the temperature, the higher the slump

The correct answer is: The higher the temperature, the lower the slump

Slump, referring to the consistency and workability of fresh concrete, is significantly influenced by temperature. Typically, as the temperature increases, the rate of hydration of the cement accelerates, leading to quicker setting times. This affects the ability of the concrete to flow and maintain a given slump value. Higher temperatures can lead to increased evaporation of moisture and may result in a faster loss of workability. As a result, the concrete mix may become stiffer more quickly, ultimately decreasing the slump. This means that when the temperature is elevated, the slump tends to be lower, as the concrete begins to set before it can be effectively placed and compacted. Therefore, understanding the relationship between temperature and slump is crucial for contractors to ensure the right consistency and performance of the concrete mix on the job site.