Pavement Surface Dynamics Friction Measurement and Analysis in Kansas: Fid-Bau Portal

Pavement Surface Dynamics Friction Measurement and Analysis in Kansas

R. E. Worley / T. M. Metheny / F. W. Stratton

Friction measurements of 277 test sections of Kansas pavement surfaces were made with a locked wheel skid trailer. Many of them were repeated several times. Stereo-photography evaluation was also conducted on some surface types. All types of construction, materials, and mix designs used in Kansas can have high skid numbers. Skid numbers are not constant for a given section of roadway or type of construction. Seasonal variation of 30 skid numbers has been measured in Kansas, so a single value is not very significant. Averages may also have little significance, as they are dependent on the number of tests and when they were run. A wide variety of materials and mixes are used in Kansas. Some materials used in certain ways indicate possible superiority, such as chert (chat) aggregate used in Portland cement concrete pavement and slurry seals, but not in hot mixes. Expanded shale and sandstone are also indicated to be good skid resistant aggregates. Seasonal variation of speed gradient was detected for all common Kansas surface types. Frosting has occurred on open-graded mixes when adjacent denser mix types remained frostless. Lightweight aggregate open-graded mixes were particularly frost susceptible.