For 3,000 psi concrete, the cylinders after 28 days should break at about how many pounds?

• A. About 90,000 pounds
• B. About 3,000 pounds
• C. About 30,000 pounds
• D. About 120,000 pounds

Answer: (A)

The test strength of 3,000 psi means the load on a standard concrete cylinder at 28 days should be around 3,000 pounds per square inch of cross-section. A typical test cylinder is 6 inches in diameter, giving a cross-sectional area of pi × (3 in)^2 ≈ 28.27 square inches. Multiply 3,000 psi by 28.27 in^2 to get about 84,800 pounds of load, which is roughly 85,000 pounds and is closest to 90,000 pounds. So the best answer is the option stating about 90,000 pounds. The other numbers don’t align with converting psi to load for a 6x12 cylinder.