AASHTO T 336 Specifies the Calibration Standard
AASHTO T 336 requires a calibration standard composed of essentially linearly elastic, non-corroding, non-oxidizing, nonporous, and nonmagnetic material with a known thermal coefficient in the range of 9 to 18 µ-strains /°C within the range of 10 to 50 °C.
The Titanium Calibration Standard
Titanium has a coefficient of thermal expansion of about 9.2 µ-strains /°C.
The Thermal Coefficient of Concrete
The thermal coefficient for concrete is approximately 9.2 µ-strains /°C.