Specimen height of 115 ± 5 mm is typical for gyration testing.

• A. False
• B. Not typical
• C. Sometimes
• D. True

Answer: (D)

In gyratory testing, the specimen’s height is set to a standard value so that every test uses a consistent volume, which makes density, air voids, and compaction behavior comparable across samples. A height around 115 mm with a tolerance of ±5 mm is the commonly specified dimension for a typical cylindrical specimen (usually of 150 mm diameter) used in this method. Keeping the height within this range ensures that the amount of material being compacted and the resulting void content follow a repeatable, reference condition. If the height were too far outside this range, the compacted density and the air voids would shift, leading to unreliable comparisons between tests. So, stating that 115 ± 5 mm is typical for gyratory testing is true.