Modification of rutting prediction model for with semi-rigid base in service based on accelerated loading test

With the rapid increase in vehicles, the load on the asphalt pavement increases, which aggravates the appearance of rutting disease. In order to establish an effective rutting depth prediction model, this study carried out accelerated loading tests (ALT) of asphalt pavement at three different temperature environments of 60 °C, 45 °C, and 30 °C for Ji-Qing Expressway at the end of service. The rutting depth of the test was measured using a Lr-70/700 laser rut measuring instrument, and the relationship between the rutting depth of asphalt pavement and the temperature change was examined. At the ambient temperature of 60 °C, three different loading speeds of 3.5 km/h, 4.5 km/h, and 5.5 km/h were tested to analyze the influence of load frequency on rutting depth. With the SPSS analysis software, the regression analysis of the collected test data was carried out to modify the rutting prediction model established by the indoor improved MTS test. The results show that when the loading speed is increased from 3.5 km/h to 4.5 km/h, the rutting depth can be reduced by 11%. When the loading speed increases from 4.5 km/h to 5.5 km/h, the rut depth can be reduced by 15.8%. When the loading temperature increases from 30 °C to 45 °C, the rut depth increases by 2.15 times. When the loading temperature increased from 45 °C to 60 °C, the rutting depth increased by 0.46 times.