North Carolina Building Contractor License Practice Exam

In construction, what strength of concrete is typically used for carport slabs subjected to severe exposure?

1. 3000 PSI

2. 2500 PSI

3. 3500 PSI

4. 4000 PSI

The correct answer is: 3500 PSI

For carport slabs that will be subjected to severe exposure, using a concrete strength of 3500 PSI is indeed appropriate. This strength level provides a solid balance between workability and durability, capable of withstanding the environmental stressors often encountered in outdoor settings, such as freeze-thaw cycles, moisture, and potential chemical exposure from vehicles or deicing agents. Selecting a concrete mix with a compressive strength of 3500 PSI ensures that the slab can hold up under significant loads while maintaining its structural integrity over time. Additionally, it offers improved resistance to cracking and surface wear, which are critical factors for carports due to the heavy traffic they experience and the outdoor conditions they face. In contrast, lower strength mixes, like 2500 PSI or 3000 PSI, may not provide sufficient resilience for a carport in a severe exposure environment, as they may degrade faster when exposed to harsh weather conditions. A higher strength mix, such as 4000 PSI, while robust, may not be necessary for standard carport applications, potentially resulting in unnecessary costs without significant benefits in most cases. Thus, 3500 PSI represents an ideal compromise for the demands placed upon a carport slab.