Plain concrete used in basement walls and foundations shall have a minimum compressive strength of how many psi?

Plain concrete used in basement walls and foundations shall have a minimum compressive strength of how many psi?

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

Answer: (A)

The main idea being tested is the minimum compressive strength required for plain concrete used in basement walls and foundations. Plain concrete in these structural elements must meet a strength of 2,500 psi (f'c) at 28 days. This level provides enough capacity to bear vertical loads from the building and resist lateral earth pressures, while also delivering adequate durability in a below-grade environment. The strength is verified by standard 28-day cylinder tests, which confirms the concrete mix meets or exceeds 2,500 psi before it is used in construction. Numbers lower than 2,500 psi (such as 1,500 psi or 2,000 psi) would generally be inadequate for structural basement walls and foundations, while higher numbers (like 3,000 psi) represent stronger mixes but are not the required minimum.

The main idea being tested is the minimum compressive strength required for plain concrete used in basement walls and foundations. Plain concrete in these structural elements must meet a strength of 2,500 psi (f'c) at 28 days. This level provides enough capacity to bear vertical loads from the building and resist lateral earth pressures, while also delivering adequate durability in a below-grade environment. The strength is verified by standard 28-day cylinder tests, which confirms the concrete mix meets or exceeds 2,500 psi before it is used in construction.

Numbers lower than 2,500 psi (such as 1,500 psi or 2,000 psi) would generally be inadequate for structural basement walls and foundations, while higher numbers (like 3,000 psi) represent stronger mixes but are not the required minimum.