According to T 312, which standard must the thermometers meet?

• A. R 68
• B. M 338
• C. M 339
• D. AASHTO M 165

Answer: (C)

Maintaining accurate temperature readings is essential for this test method, since the results depend on precise heat measurements during sample handling and testing. The standard that thermometers must meet is the one that specifically defines the performance, calibration, and traceability requirements for thermometers used in this context. That standard sets the acceptable accuracy, the calibration procedures, and the range needed for the temperatures involved in T 312, ensuring that all labs obtain consistent and comparable results.

The other options cover instruments or guidelines that don’t address the thermometer performance required for this asphalt testing method, so they aren’t the appropriate choice.