The wheel tracking apparatus consists of a loaded wheel, which bears on a sample held on a moving table. The table reciprocates with simple harmonic motion through a distance of 230 ± 5 mm with a frequency of 53 passes (± 1%) per minute. For reasearch purposes the test speed can be adjusted by inverter control. The wheel is fitted with a solid rubber tyre of outside diameter 200 mm. The wheel load under standard conditions is 700 ± 10 N.
The wheel tracker is fitted with a temperature controlled cabinet with a temperature range from environment to 65°C ± 1.0°C.The sample may be either a 200 mm diameter core or a 300 x 400 mm slab of asphaltic mixture from 25mm to 100 mm thick. A 25 mm stroke LVDT transducer is included for monitoring rut depth in the centre of a sample during a test to better than 0.1 mm.
The deformation and sample temperature is recorded by the internal data acquisition and control system, then sent to the Windows® compatible software.
Sample confinement frames