Equivalent Temperature for Asphalt Surface Layer and Modified Coefficient to Fatigue Life Based on Subgrade Compression Strain

Abstract:

Based on subgrade compression strain index and the equivalency principal of cumulative fatigue damage, conception and calculation method of equivalent temperature for asphalt surface layer were put forward. The relationship between the temperature condition of asphalt surface layer and subgrade fatigue life was analyzed. The law of equivalent temperature for asphalt surface layer was summarized. By introducing modified coefficient to subgrade fatigue life, regression formula among modified coefficient , the altitude of asphalt pavement located, pavement surface average temperature and its standard deviation over the years was established. Accordingly, modified coefficients at 738 areas in China were calculated and a contour map of was draw. Then simple and practical regression formula between modified coefficient and two common meteorological parameters: annual average temperature and difference of the highest and lowest monthly average temperature was established. Finally, the influence rules of various factors on modified coefficient to subgrade fatigue life were summarized and approximate modified formula was given.