Description

The wheel tracking test is used for determining the susceptibility of Hot Mix Asphalt (HMA) to deform under load by measuring the rut depth formed by repeated passes of a loaded wheel at a fixed temperature. 

This universal version complies either to AASHTO or EN standards being equipped with both stainless steel and rubber wheels, and performing the test in air or water. This solution is particularly suitable for research laboratories.
This  version can be upgraded with automatic system which lift one of the wheel from the specimen that has reached the rut target continuing the test on the other specimen. See Upgrading options Automatic wheel lifting mechanism.

The Double Wheel Tracker can be used as part of your Superpave performance based testing program.

Machine body
Sheet steel, powder coated. Trasparent sliding doors.

Loaded wheel system
This Universal model is fitted with double stainless steel wheel, 203 mm dia. x 47 mm wide, and double solid rubber tyre, 203 mm dia. x 50 mm wide.
The wheel load is adjustable in 100 N steps from 700 to 1500 N (for 77-PV33D05-06 only). The system includes a motorized lifting system of the wheel assembly at the end of the test.

Wheel tracking carriage
The wheel is moved 230 mm backwards and forwards on the top of the slab, which is fixed. The speed is adjustable via the PC from 20 to 30 cycles per minute (40 to 60 passes). The longest slab dimension is oriented to the wheel's direction of travel. Special slab moulds for circular samples obtained from coring or gyratory compactors are also available. See accessories.

Temperature control system
The AASHTO Hamburg type Standard states that the test must be performed in a water bath over a range of 25 to 70°C ± 1.0°C, whilst the EN requires either air or water environment. In both systems a water level of about 20 mm above the sample has to be maintained. Where a heated air environment is specified, the specimen, during testing, must be maintained at uniform and constant specified temperature ± 1° C.  All versions fully satisfy and exceed  the above requirements: the temperature accuracy is ±0.5°C.

Temperature controlled cabinet
The Universal AASTHO/EN versions feature an inbuilt temperature controlled cabinet for testing in air or in water, designed to avoid condensation problem (in water testing) and prevent overtemperature which may damage the mechanical parts or alter the transducer accuracy. Furthermore the system ensure thermal stability and provides rapid test start when the conditioned temperature has been reached.

Impression measurement system
Each wheel is fitted with linear transducer measurement system for deformations 0 to 50mm ±0.01mm.

• Full conformity to EN, DOT methods (including TxDOT TEX-242-F) and AASHTO T324-19, including sinusoidal movement (RMSE certificate available on request) and rut depth measurement in 11 defined points
• Fully automatic test performance on two specimens or one specimen
• Variable wheel speed from 20 to 30 cycles/min
• Fixed table, mobile wheel 230 mm travel
• Wheel load of 700/705 N or adjustable from 700 to 1500 N
• Temperature range from ambient to 80°C (±0.5°C)
• Accurate temperature control (±0.5°C) for both in water and air test
• Ruth depth transducers feature 50 mm travel, 0.01 mm accuracy
• Direct rut depth measurement system, with transducers axially mounted in alignment with the wheel's centre
• Motorized wheel-assembly lifting system for easy removal of slabs
• Free access to the wide testing area
• Optional independent lifting system for double or single wheel testing
• Slab mould size of 400x300 mm, 360x300 mm (for 320x260 mm slabs), double 150 mm gyratory compactor cylinders, 200 mm/8"/10" diameter cores
• Slab thickness adjustable from 40 to 100 mm (in 10 mm steps)
• Extensive use of stainless steel in the machine's construction; not limited to the parts in contact with water
• Laptop PC control with dedicated software including results performance, test database management and multiple test elaborationAutomatic water filling and leveling system, no need to adjust or control the water level above the specimen during test
• The software includes the possibility to program pre-heating and machine start (without operator intervention) and to measure the rut depth measurement in user-defined positions for research purposes or local specifications