Quantify pavement segregation

Since the identification of segregation on asphalt pavements has been based on visual observations in Taiwan, it is essential to develop a quantitative method to detect presence and severity of segregation. The non-nuclear density device was selected for the field measurements at nine test sites, and cores were taken for laboratory testing. The non-nuclear density difference between segregated and control areas was found to increase with increasing the segregation severity. For medium or heavy segregated areas, the non-nuclear density difference was more than 90 kg/m³. Analyses of the results showed that there was a significant increase in surface texture depth of segregated areas as compared to control areas. In medium or heavy segregated areas, the air voids increased by 20% and the indirect tensile strength decreased by 8% as compared to the control area. The criterion to detect segregation was based on the statistical differences in non-nuclear measured density values with a p-value 0.05. If a statistical difference in non-nuclear density between segregated and control areas existed, the chance of aggregate gradation difference in percent passing the 3/8", No. 4 and No. 8 sieves for medium and heavy segregation was 78% and 64%, respectively.