ASTM E1859/E1859M-24

Detail information

Designation: ASTM E1859/E1859M-24

Publication date: 01/11/2024

Pages: 8

Country: American technical standard

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Anotation

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. The test apparatus consists of an automotive vehicle with one or two independently functioning test wheel systems incorporated into it. Each test wheel system contains a continuously variable brake system and a pavement wetting system. The overall system is controlled by a programmable control unit. The test apparatus is brought to the desired test speed. A controlled amount of water is optionally delivered ahead of the test tire and the braking system is actuated to control the slip ratio of the test wheel. The resulting resistive force from friction acting between the test tire and pavement surface is sampled, filtered, calculated, and recorded by suitable data acquisition routines. For tire comparison testing two identical test wheels, both are subjected to the same test run control logic for equal spin velocities and loads in parallel wheel paths on the same test track. The braking slip friction coefficient of the paved road surface is calculated and reported as slip friction numbers. The slip friction numbers are typically presented in a graphical form. Cartesian plots of slip friction numbers versus slip speed or slip ratio are presented with identification of: peak friction value, critical slip ratio, slip-to-skid friction number, slope of the tangent at zero slip speed of the curve, and slope of the logarithm curve at high slip ratio.


Keywords:
ICS Number Code 83.160.01 (Tyres in general),93.080.99 (Other standards related to road engineering)