Which statement accurately describes the oven temperature specification for drying aggregate samples?

• A. 120 ± 10 °C within 90–180 °C
• B. 100–150 °C with no tolerance
• C. 90–100 °C
• D. 110 ± 5 °C, with 100–200 °C range and ±5 °C tolerance

Answer: (D)

Drying aggregate samples in the oven is all about removing moisture reliably without changing the material itself. The best practice uses a temperature around 110 °C with a tight tolerance of ±5 °C. This level is high enough to evaporate water quickly, but not so hot that it alters mineral structure or causes loss of fines or other changes in the aggregate. The small tolerance ensures that different tests and different labs produce nearly the same dry mass, which is crucial for accurate moisture content calculations. If the temperature were allowed to swing widely or fall too low, drying would be inconsistent, taking longer or risking incomplete moisture removal or changes to the material. Therefore, a fixed target near 110 °C with a narrow tolerance is chosen to balance speed, accuracy, and material integrity, and you dry until the mass stabilizes.