Alabama Contractors License Practice Exam

What is the minimum compressive strength in psi for a concrete basement slab with negligible weathering potential?

1. 1,500 psi

2. 2,000 psi

3. 2,500 psi

4. 5,000 psi

The correct answer is: 5,000 psi

The minimum compressive strength for a concrete basement slab with negligible weathering potential is essential because it determines the slab's ability to withstand loads and ensure longevity. A compressive strength of 5,000 psi is commonly recommended for structural applications, especially in areas where the concrete may be subjected to substantial loads or potential moisture infiltration, which is often the case in below-grade structures like basements. Using a concrete mix with this strength provides assurance that the slab will have sufficient durability and load-bearing capacity while minimizing the risk of cracking or failure over time. Although lower strengths, such as 1,500 psi, 2,000 psi, or even 2,500 psi, might be adequate for non-structural purposes, they do not align with best practices for the critical role a basement slab plays in overall building integrity and performance in varying environmental conditions. By opting for a minimum of 5,000 psi, contractors ensure that the basement slab can adequately handle any unforeseen stresses and maintain its structural integrity throughout its service life.