ASTM International

Standard Test Method for Friction Coefficient Measurements Between Tire and Pavement Using a Variable Slip Technique
 N E1859/E1859M

Annotation

This test method covers the measurement of the longitudinal friction coefficient with a measurement device that imposes braking-slip between a tire and a surface for the full range of braking-slip speed values.

This test method utilizes a series of incremental single measurements of friction force on a braked test wheel as it is pulled over a wetted or contaminated pavement surface. The rotational velocity of the braked wheel is feedback controlled in order to give a predetermined variable slip ratio gradient in accordance with set program parameters. The test wheel is kept under a constant static normal load and at a constant longitudinal speed of travel. Its major plane is perpendicular to the road plane and parallel to its direction of motion.

The values measured represent the friction properties obtained with the equipment and procedures stated in this test method and do not necessarily agree or correlate directly with those obtained by other pavement friction measuring methods.

The values are intended for use in:

Evaluating the braking friction forces on a pavement relative to that of other pavements.

Evaluating changes in the braking friction forces of a particular pavement with the passage of time.

Evaluating the changes in the braking friction force of a pavement when subjected to polishing wear and loss of macrotexture caused by traffic with passage of time.

Evaluating changes in the braking friction forces of a pavement contaminated with ice, moderate amounts2 of slush and snow, pollen, vehicle oil spills and condensates from vehicle engine exhaust, and deposits from other pollution sources.