DWT Double Wheel Tracker

The DWT Double Wheel Tracker with unique solutions to perform the test with the maximum reliability

MAIN FEATURES

• Meets and exceeds EN standards
• 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 N
• Temperature range from ambient to 80°C (±0.5°C)
• Accurate temperature control (±0.5°C) for both in water and air test
• Rut depth transducers feature 25 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 400×300 mm
• 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
• PC and software included
• Automatic water filling and leveling system, no need to adjust or control the water level above the specimen during test
• Possibility to add two optional temperature probes to monitor the two samples temperature
• Laptop PC control with dedicated software including results performance, test database management and multiple test elaboration

GENERAL 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. Two versions available as prescribed by EN 12697-22 Small Size device: specimen conditioning in air and in air or water.
Both versions 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.
We also produce Wheel Trackers conforming to AASHTO T324 standard and a universal version conforming to both AASHTO and EN standards. See Hamburg type double wheel tracker and Universal AASHTO/EN double wheel tracker.

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

Loaded wheel system
The EN versions are fitted with double solid rubber tyre, 203 mm dia. x 50 mm wide.
The wheel load is 700 N. The system includes a motorized lifting system for raising 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 EN prescribes either air or water environment. 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. The DWT Double Wheel Trackers fully satisfy and exceed the above requirements: the temperature accuracy is ± 0.5°C.

Impression measurement system
Each wheel is fitted with RUT DEPTH transducers for measuring deformationsfrom 0 to 40 mm ±0.01 mm.