Accelerated Polishing Machine, ASTM/AASHTO Compliant

Accelerated Polishing Machine, ASTM/AASHTO Compliant

The Accelerated Polishing Machine is an essential piece of equipment used to determine the polished stone value (PSV) of aggregates, which measures their resistance to the polishing action of vehicle tires. This value is crucial for assessing the suitability of aggregates for use in road surfacing, as it directly relates to skid resistance and road safety.

How it works: The machine simulates real-world road conditions in a controlled laboratory environment. The process begins by embedding aggregate samples, typically between 3/8 and 1/2in (9.5–12.7mm), into fourteen curved molds. These segments are then clamped together around a "road wheel" to form a continuous testing surface, which is 1-3/4in (44.5mm) wide and has a diameter of 16in (406mm).

During the test, the road wheel rotates at a constant speed of 320 ±5rpm while in contact with a solid rubber-tired wheel. Abrasives are consistently fed into the contact area to accelerate the polishing process. The machine applies a constant load of 88lbf (391N) to simulate the pressure of vehicle traffic. A gravity-fed water system keeps the surface wet, mimicking wet road conditions, and washes away used abrasive, which is collected in a removable tray.

After the polishing cycle is complete, the friction characteristics of the polished aggregate specimens are measured using a Pendulum Skid Tester. This provides the data needed to calculate the PSV.

Construction and Design: Built to comply with ASTM D3319, AASHTO T 279, and BS 812/EN 1097-8 standards, the Accelerated Polishing Machine features a robust, welded steel frame mounted on adjustable leveling pads for stability. It is powered by a reliable TEFC (Totally Enclosed, Fan-Cooled) motor with an adjustable timing belt drive. An electronic preset revolution counter ensures that tests are automatically terminated after the specified duration, guaranteeing accuracy and repeatability. The machine also includes a precision grit feeder and a Goodyear pneumatic-tired wheel assembly.

Features:

• Accurately simulates the polishing effect of tires on road aggregates.
• Fully compliant with ASTM D3319, AASHTO T 279, and BS 812/EN 1097-8 standards.
• Automated test termination via a preset revolution counter for consistent results.
• Durable steel frame ensures long-term stability and performance.
• Includes a calibrated flow meter for precise water control.
• Mechanical lifting device for safe and controlled tire loading.

Included Items:

• Accelerated Polishing Machine
• Two (2) Specimen Molds
• Two (2) Mold Plates
• Required Abrasive Feeders
• Pneumatic-Tired Wheel Assembly
• Set of Wrenches
• Mounting Pads
• Detailed Operating Instructions

Required Accessories (Ordered Separately):

• Abrasives: The test requires both Corn Emery and Silicon Carbide Grit. Each test consumes approximately 10lb (4.5kg) of silicon carbide grit.
• Pendulum Skid Tester: Necessary for measuring the friction value of the polished samples.

Product Dimensions: 30 x 28 x 42in (762 x 711 x 1067mm), WxDxH

Meets Standards:

• AASHTO T 279
• ASTM D3319
• BS 812
• EN 1097-8