General Contractor Practice Exam

What is the minimum PSI for concrete slabs and steps that are exposed to moderate weathering?

1. 2500 PSI

2. 3000 PSI

3. 3500 PSI

4. 4000 PSI

The correct answer is: 3000 PSI

The minimum PSI (pounds per square inch) for concrete slabs and steps exposed to moderate weathering is 3000 PSI. This strength is crucial because it ensures that the concrete can withstand various environmental conditions, including freeze-thaw cycles, which can cause significant deterioration if not properly addressed. Concrete with a PSI of 3000 is generally considered suitable for moderate exposure where it may be subjected to some degree of weathering, moisture, and temperature fluctuations. This level of strength provides adequate durability for applications such as sidewalks, steps, and slabs that will face moderate climatic conditions. Higher PSI values, such as 3500 or 4000 PSI, may offer additional durability and resistance to weathering but are not necessary for moderate exposure scenarios. The lower PSI of 2500 would not provide sufficient durability for these conditions, making it an unsuitable choice. Therefore, 3000 PSI is the minimum strength recommended for ensuring the long-term performance and integrity of concrete in moderate weathering environments.