In the Method C procedure, at what temperature should the oven be regulated?

• A. The oven must be regulated at ± 350 °F.
• B. The oven must be regulated at ± 200 °F.
• C. The oven must be regulated at ± 300 °F.
• D. No oven is used.

Answer: (C)

In Method C, controlled oven heating is used to dry the sample consistently without altering its composition. The temperature is set to about 300 °F, with the specification allowing a drift around that value. This level is high enough to remove moisture and volatile components efficiently, while still staying below the point where the asphalt binder could begin to oxidize or degrade.

Choosing a much higher temperature, like 350 °F, risks damaging the binder and changing the test outcome. A temperature as low as 200 °F may not be sufficient to fully dry the sample in the allotted time, leading to errors. And not using an oven at all would ignore the standardized drying step required by the procedure.

So, the correct approach is to regulate the oven at about 300 °F.