Dynamic Friction Tester (DF Tester)

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Overview

The Dynamic Friction Tester (DF Tester) is a portable instrument for measuring pavement surface friction as a function of speed and under various conditions. The instrument is comprised of a measuring unit and a control unit; an x-y plotter or laptop can be used to record data. The measuring unit consists of a disc made to rotate horizontally at a specified velocity before being lowered onto a wetted test surface for measurement of friction. The torque-generated by the resistance between the test surface and spring-loaded rubber "sliders" attached to the underside of the rotating disc-is continuously monitored and converted to a measurement of friction.

Applicable Test Standard(s)

ASTM E1911, Measuring Paved Surface Frictional Properties Using the Dynamic Friction Tester

Device Features (Saito et al. 1996)

• Measured values are a continuous spectrum of dynamic coefficient of friction with good reproducibility.
• Measurement can be made in a very short time.
• The device is designed to be compact and easy to handle.
• Coefficient of friction is reported as a function of speed at a contact pressure similar to that of typical motor vehicles.
• The device is powered by 12V DC (e.g., battery of vehicle transporting the device).
• Coefficient of friction is graphically plotted in a continuous spectrum for each measurement.
• The standard rubber of the slider assembly is synthetic rubber meeting ASTM E501.
• The slider assembly can be easily replaced onsite, allowing the friction characteristics of different rubber materials to be investigated.

Dimensions and Weight

References

Saito, K., T. Horiguchi, A. Kasahara, H. Abe, and J.J. Henry. 1996. "Development of Portable Tester for Measuring Skid Resistance and Its Speed Dependency on Pavement Surfaces." Transportation Research Record, No. 1536. Washington, D.C.