Crushing Strength Of Concrete Block. Cube Test Compressive Strength of Concrete Block after Properties of Concrete Blocks — Strength Two blocks 6X8X9 inches, 22 months old, showed crushing strength of 2,530 and 2,610 pounds per square inch. These blocks were made of cement 1.25 parts, lime 0.5 part, sand and gravel 6 parts, and were tamped ...