Which statement about ashing temperature is true?

• A. Samples should be ashed at a temperature between 500-600 °C.
• B. Samples should be ashed at room temperature.
• C. Ammonium carbonate should be added to the ash before ashing.
• D. The ash weight is used to compute binder content directly.

Answer: (A)

Ashing temperature must burn off the asphalt binder without harming the mineral aggregate. Using a temperature in the 500–600 °C range achieves this balance, typically around 550 °C, so the binder is removed while the aggregate stays intact and the ash represents the inorganic material left behind. Ashing at room temperature would not remove the binder, so the result wouldn’t reflect the binder content. Adding ammonium carbonate is not part of the standard procedure and would contaminate the ash. Binder content is determined from the loss in mass (the difference between the original sample weight and the ash weight), not directly from the ash weight itself.