Laboratory Evaluation and Statistical Analysis of the Effects of Contaminants on Skid Resistance of Asphalt Pavement

One of the important properties road pavement and safety is skid resistance. These properties are dependent on numerous factors, such as properties of pavement surface texture and materials used, weather conditions, seasonal changes and road surface contaminants. The aim of this study is to examine the effects ofvarious contaminants on skid resistance of the pavement surface. The existence of contaminants, especially during the first rain after a drought period makes the wet 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. So, in this study, dust, quick sand, lube oil, rubber particulates, soot and cool color traffic were chosen as contaminants. Asphalt samples were made in Marshall large formats using three continuous grading with Gyratory compression and then by British Pendulum Tester were tested at different temperature and humidity. Test results indicated that contaminants had distinct effects on skid resistance of asphalt pavements. It was also shown that under dry conditions, the minimum value of skidding is when the surface is completely covered with quicksand and under wet conditions; the value of skidding was declined on average of 49 to 55 percent by cool color traffic. Artificial neural network (ANN) and decision tree data-mining methods were employed to analyze the data were derived from the statistical model. Accordingly, it was shown that changes in the type of contaminants cause the greatest change in skid resistance.