Significance of initial rutting in prediction of rutting development and characterization of asphalt mixtures

Wheel tracking testing on AC-20 limestone and AC-13 basalt asphalt mixtures was carried out to investigate the significance of initial rutting in prediction of rutting development and characterization of asphalt mixtures. Stress, temperature and moisture affected rutting, however, the effect of temperature and stress on rutting became significant at temperatures higher than 50 °C and loading cycles greater than 1000. Short-term and long-term rutting development could well be predicted from initial rutting values using linear and exponential functions respectively, with 1000 cycles considered the shift loading cycles for rutting prediction. Threshold initial rutting values for mixture characterization were determined based on past studies and JTG E20-2011 standard. They were validated using wheel tracking results of AC-25 recycled hot mix asphalt and AC-20 mixtures under water immersion, and could thus be used for quick rutting prediction and mixture optimization.