Developing Field Skid Resistance Prediction Procedure for Louisiana Pavements

Research shows that by improving pavement surface friction resistance, wet pavement crashes can be reduced or prevented. However, the current asphalt mixture design procedure does not directly consider friction as a design requirement. The main objective of this study was to develop a procedure to predict the pavement field skid resistance based on design traffic input, aggregate polishing, and mixture properties commonly available during a mix design. Twenty-two asphalt pavement test sections were considered in this study. The selected asphalt mixtures consisted of eight commonly used aggregates and four typical mix types: 12.5-mm Superpave, 19-mm Superpave (R), stone mastic asphalt, and open-graded friction course. Field measurements were conducted with the dynamic friction tester, circular texture meter, and locked-wheel skid tester devices, while the coarse aggregate's polished stone values were determined by using the accelerated polishing test in the laboratory. Statistical analysis of various field and lab test results led to the development of a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend's polished stone values, gradation parameters, and design traffic input. In addition, a new aggregate friction rating table was developed so that new aggregate sources can be certified by laboratory dynamic friction tester measurements to fulfill the required mixture friction requirements. The new procedure will allow engineers to check whether a mix design with a selected blend of aggregates would meet field friction requirements during the mix design stage.