Fractal Evaluation of Pavement Skid Resistance Variations. I: Surface Wetting

Pavement skid resistance has long been recognised as the primary factor to reduce traffic accidents. Skid resistance is affected by a large number of parameters. This is the first in a series of two papers dealing with the road surface contribution to tire-pavement skid resistance giving special emphasis to the effect of a water film development on the pavement surface. Pavement surface texture is expressed by micro macrotexture depth and density. Relative regression equations giving pavement skid resistance values have been reviewed and a well fitting regression equation has been derived. The mathematical background of fractal interpolation functions is then presented. An attempt is described to approximate the pavement surface texture with fractals by taking into account its accurate geometry. Through this approximation the procedure of pavement surface wetting is evaluated, in respect with its effect to skid resistance values. This attempt yields encouraging results, although it is apparent that further research is required.