For AASHTO MP1 tests a sample disc is confined between circular parallel plates and tested at a specific temperature.

Dynamic shear is determined by applying a known torque to oscillate one of the plates and measuring the resulting strain.

The phase angle, in radiants or degrees between the sinusoidal stress & strain, is measured, too.

Resultant stress is measured in a strain control mode, while resultant strain in a stress control mode.

Automatic Dynamic Shear Rheometer Test Equipment

More details are mentioned in the "Order Number" section