According to code, what is the minimum compressive strength (psi) for plain concrete used in basement walls and foundations?

According to code, what is the minimum compressive strength (psi) for plain concrete used in basement walls and foundations?

• A. 1500 psi
• B. 2500 psi
• C. 3000 psi
• D. 2000 psi

Answer: (B)

The main idea is that codes specify a baseline compression strength for plain (unreinforced) concrete used in structural elements like basement walls and foundations. For these plain concrete applications, 2,500 psi is the minimum strength required. This level provides adequate resistance to the vertical loads of the structure and the lateral earth pressures acting on basement walls, while keeping the mix practical and cost-effective since there’s no reinforcing steel to carry tensile forces. Lower strengths would not meet the structural needs, and higher strengths are typically used for reinforced concrete or specific high-load conditions rather than bare plain concrete.

The main idea is that codes specify a baseline compression strength for plain (unreinforced) concrete used in structural elements like basement walls and foundations. For these plain concrete applications, 2,500 psi is the minimum strength required. This level provides adequate resistance to the vertical loads of the structure and the lateral earth pressures acting on basement walls, while keeping the mix practical and cost-effective since there’s no reinforcing steel to carry tensile forces. Lower strengths would not meet the structural needs, and higher strengths are typically used for reinforced concrete or specific high-load conditions rather than bare plain concrete.