QUANTITATIVE STUDIES ON THE RELATION BETWEEN THE ROUGHNESS AND THE COEFFICIENT OF FRICTION OF ROAD SURFACES

QUANTITATIVE UNTERSUCHUNGEN UEBER DEN ZUSAMMENHANG ZWISCHEN DER RAUHIGKEIT UND DEM REIBUNGSWERT VON STRASSENDECKEN

THE AIM OF THE PROJECT IS TO ESTABLISH THE COEFFICIENT OF FRICTION EMPIRICALLY AND TO DETERMINE A CAUSAL RELATION BETWEEN THIS AND THE SURFACE CONDITION (ROUGHNESS) OF ROAD SURFACES. THE CONCEPT OF ROUGHNESS MAY BE DEFINED BY STUDYING AVERAGE ROUGHNESS DEPTH, DISTRIBUTION OF ROUGHNESS DEPTHS AND THE RADII OF CURVATURE OF ROUGHNESS PROFILES. THESE MAGNITUDES ARE BEING QUANTITATIVELY DETERMINED BY SAMPLING AND SUBSEQUENT MICROSCOPIC STUDIES, AND A METHOD OF MEASUREMENT IS BEING DEVELOPED. ONE METHOD CONSISTS OF A POINTED TESTING HEAD INCORPORATING AN INDUCTIVE SENSOR. VALUES OBTAINED WITH THIS MAY BE COMPARED WITH THOSE DETERMINED OPTICALLY. BY MEANS OF COMPREHENSIVE SERIES OF TESTS ON VARIOUS ROAD SURFACES THE ROUGHNESS DEPTH DISTRIBUTION AND THE DISTRIBUTION OF RADII OF CURVATURE OF THE PROFILES CAN BE DETERMINED AND COMPARED WITH RESULTS OBTAINED FROM THE TOWED WHEEL TEST.