Associate professor, College of Petroleum and Minerals, Dhahrau,
Professor of civil engineering, Texas A&M University, College Station, Texas
Research engineer, Texas A&M University, Texas Transportation Institute, College Station, Texas
Accurate measurement of highway skid resistance has required the application of appropriate reference standards for the calibration of locked wheel skid trailers [ASTM Test for Skid Resistance of Paved Surfaces Using a Full-Scale Tire (E 274-70)] used as test equipment. This investigation was concerned with the development of criteria needed for the design of primary standard reference pavement surfaces.
A review of previous research indicated that the pavement variables influencing tire-pavement friction should be expressed in terms of six surface texture parameters. Pavement macrotexture, with characteristic dimensions between 2 and 16 mm, was expressed in terms of asperity size, spacing, and shape. The remaining three parameters, which described asperities with characteristic dimensions less than 2 mm, were expressed as microtexture size, spacing, and shape. Published studies indicated that surface texture influenced wet tire-pavement friction through water drainage, hysteresis losses in the tire, and adhesion in the tread contact area. Published equations relating pavement texture and firction have been derived on the basis of oversimplified models and, thus, required considerable experimental support to be applicable to the design of reference pavement surfaces. In particular, the theory treating the effect of surface microtexture on the adhesion component of friction was found to be incomplete, both analytically and experimentally.
A parametric study of the effect of pavement texture on skid number, comprising laboratory experiments with model pavement surfaces, offers new insight to a solution of the problem.
Paper ID: JTE10078J