Commercial Building Inspector B2Floor ConstructionEasy
A commercial building inspector is observing the installation of a new concrete floor slab on grade for a warehouse. The plans specify a 6-inch thick concrete slab. What is the minimum compressive strength required for concrete used in a slab-on-grade for a warehouse, assuming no special conditions are noted beyond typical industrial use?
- A2,000 psi
- B3,500 psi
- C3,000 psi
- D2,500 psi
Show answer & explanationAnswer & explanation
Correct answer: D. 2,500 psi
For typical concrete slab-on-grade applications, especially in commercial or industrial settings like a warehouse, the minimum specified compressive strength (f'c) is generally 2,500 psi, unless higher strength is specifically required for structural loads or durability.
Why the other options are wrong
- A. This strength is typically for non-structural fill or very light-duty applications, not suitable for a warehouse slab.
- B. This strength is for applications requiring significantly higher load-bearing capacity or enhanced durability, exceeding the typical minimum for this scenario.
- C. While often used, 3,000 psi is a common choice for increased durability or higher loads, but not the absolute minimum for typical warehouse slabs.
Slab-on-Grade Concrete Strength
The minimum specified compressive strength (f'c) for concrete used in floor slabs directly supported by grade.
- Typically 2,500 psi for general commercial/industrial use.
- Higher strengths may be required for heavy loads or specific environmental conditions.
- Specified by structural engineer and concrete mix designer.
Memory trick: For a solid slab, 2500 is the strong foundation start.