Field Evaluation of Asphalt Mixture Skid Resistance and Its Relationship to Aggregate Characteristics (0-5627-3)

This report documents the findings from the research that was carried out as part of Phase II of TxDOT Project 0-5627. The research included measurements and analysis of mechanical and physical properties of aggregates used in surface mixes in the state of Texas. These properties were aggregate shape characteristics measured using the Aggregate Imaging System (AIMS), British Pendulum value, coarse aggregate acid insolubility, Los Angeles weight loss, Micro-Deval weight loss, and Magnesium sulfate weight loss. In addition, a database of field skid number measurements that were collected over a number of years using the skid trailer was developed. The Dynamic Friction Tester (DFT) and Circular Texture Meter (CTMeter) were used to measure friction and texture, respectively, of selected asphalt pavement sections. These data and measurements were used to carry out comprehensive statistical analyses of the influence of aggregate properties and mixture design on skid resistance value and its variability. Consequently, a method and software were developed for predicting asphalt pavement skid resistance. This method requires inputs that describe aggregate resistance to polishing, mixture gradation, and traffic. The developed software can be used to select the mixture type and aggregate source that are needed to achieve the required level of skid resistance for a given service life.