Permafrost Regions Of Asphalt Mixture At Low Temperature Crack Resistance And Mix Design Method

The asphalt mixture's crack resistance at low temperature is one of the key pavement performances in perennially frozen soil zone, and aging procedure has important effect on it. Presently research and evaluation method on it are very limited. Through bending creep test at 0C and bending test at -10C, this thesis studies the crack resistance at different aging condition. Research shows that the aging procedure will greatly reduce the asphalt mixture's crack resistance. Research also shows that in different test condition, sensitivity, accuracy, and stability of bending creep test at 0 C are better than that of bending test at -10C. Thus, bending creep test at 0C can preferably evaluate the crack resistance of asphalt mixture at low temperature.Based on the test result, considering the key pavement performances in the perennially frozen soil zone such as crack resistance, aging resistance and freezing resistance, this thesis puts forward the asphalt mixture design method for perennially frozen soil zone. Compared to specification's Marshell Method, this method reduces percentage of voids value, throws away flow value index. Furthermore, it adds freezing resistance index and bending creep speed at 0C as a control index of aging resistance and crack resistance. Finally, it adjusts the temperature of rut test index.