What is the minimum size sample for making strength test specimens?

• A. 0.5 cubic foot
• B. 1 cubic foot
• C. 1.5 cubic feet
• D. 2 cubic feet

Answer: (B)

The main idea is that strength results must come from a sample large enough to represent the whole material. A minimum of one cubic foot gives enough material to cast standard test specimens and to cure them under consistent conditions, so the measured strength reflects the batch rather than a local pocket of unusually strong or weak material. With less than this, small-scale variations, moisture, compaction, or curing differences can dominate the result, making it less reliable. So, one cubic foot strikes a practical balance, providing a representative sample for accurate strength testing.