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Accelerated Polishing Machine

The Cooper Accelerated Polishing Machine is the industry standard device for the determination of the Polished Stone Value PSV

Accelerated Polishing Machine CRT-APM was first manufactured over 30 years ago. In the 1950’s increased traffic flow and higher speeds, together with concerns about road safety led to research into the relationship between road materials and skid-resistance. Research at the UK Transport Road Research Laboratory showed a significant relationship between polishing of aggregates used in road surfaces and skid resistance. Tests were devised using an Accelerated Polishing Machine and a friction measuring device, known as the Pendulum Skid Tester (also manufactured by Cooper), to determine a Polished Stone Value (PSV).
Fourteen specimen aggregate samples are clamped around a rotating road wheel. These samples are subjected to two timed stages of abrasive polishing under a loaded rubber tyre. First by Corn Emery grit, and secondly by Flour Emery powder.
With the best quality as market leaders, Cooper have recently been copied by low quality manufacturers. Imitators’ machines may look similar, but precision, repeatability and reproducibility come only with years of experience.


  • EN 1097-8:2009 (formerly BS 812 pt114: 1989)
  • ASTM E303-93
  • ASTM D3319-99

Key Features

  • High ground steel main spindle running in precision sealed ball bearings. Additionally protected by a labyrinth seal spindle, axially loaded to eliminate end play
  • Adjustable 3 phase motor speed control with adjustable timing belt drive, reducing power consumption and improving control
  • Inverter drive to motor for precise speed control
  • Digital display preset timer and revolution counter
  • Robust welded steel mainframe, standing on adjustable pads
  • Specimens manufactured and easily removed from precision machined moulds
  • 14 Specimens located on ‘Road Wheel’ by rubber rings and held by simple side fixing
  • Tyred wheel easily removed for replacing tyres
  • Water gravity fed from high level tank through calibrated flow meter
  • Used abrasive and water collected in easily removable tray
  • Loaded tyre raised and lowered to the running surface by mechanical lifting device
  • Protection by covers and guards may be easily removed for maintenance
  • CE marked
  • ASTM option with pneumatic wheel

  • Key Use

  • To produce polished stone samples of aggregates used in road surfaces, to simulate actual road conditions
  • Accessories

    Accessories are not included in the price of main device (unless stated otherwise) and may be purchased separately if required.

    CRT-APM-886 Base Plate
    CRT-S882/190 Corn Emery 20Kg Bags (Graded)
    CRT-S882/191 Flour Emery 20Kg Bags (Graded)
    CRT-APM-S882/200 Corn Emery 20Kg Bags (Ungraded)
    CRT-APM-S882/201 Flour Emery 20Kg Bags (Ungraded)


    Technical specifications are subject to change without notice.

    Road Wheel Speed (rev/min) 320 ± 5
    Tyred Wheel Set Diameter (mm) 200 ± 3
    Tyred Wheel Set Width (mm) 38 ± 2
    Tyred Wheel Hardness (mm IRHD) (69 ± 3)
    Applied Load on the Wheel (Newtons) (725 ± 10)
    Electrical Supply 230V/110V. 50/60 Hz Single Phase 13Amps
    Dimensions (mm) (W x D x H) 810 x 790 x 1230
    Water Tank Height (mm) 1550
    Palletised Dimensions (mm) (W x D x H) 1200 x 800 x 1280
    Weight (approx.) Kg 210
    Volume cubic meters 0.79

    Calibration & Maintenance

    Calibration, Annual Service and Maintenance Contracts are available for this device.
    Please enquire for further details. Note: This device should be checked and calibrated annually.