Laboratory evaluation and statistical analysis of the effects of pollutants on asphalt pavement skid resistance

One of the important properties of roads related to road pavement and safety is skid resistance. These properties is dependent on numerous factors, such as properties of pavement surface texture and materials used, weather conditions, seasonal changes and road surface contaminant. In this study the effects of various contaminants on skid resistance of the pavement surface were investigated .The presence of contaminants, especially during the first rain after a drought period makes road surfaces slippery and increases the risk of accidents. Some of these contaminants are natural such as dust and quick sand on the desert areas and some of them are unnatural such as lube oil and rubber particulates produced by tire wear. In this study, dust, quick sand, lube oil, rubber particulates, soot and cool color traffic were chosen as contaminants. Asphalt samples using three continuous grading with Gyratory compression were made in Marshall large formats and by British Pendulum Tester were tested at different temperature and humidity. It was proved that contaminants affected skid resistance of asphalt pavements distinctly. It was also shown that in the dry conditions, the minimum value of skidding is when the surface is completely covered with quick sand and in the wet conditions; the value of skidding was declined on average 49 to 55 percent by cool color traffic. The data were derived from the Statistical model, were analyzed by decision tree and artificial neural network. It was shown that changes in the type of contaminants cause the greatest change in skid resistance.