To imp rove the performance of asphalt pavement, the dynamic and static tests of asphalt were used to measure its viscoelastic properties under different time. Based on the obtained data of static creep compliances and dynamic compliances according to the static creep test and dynamic test of asphalt using the dynamic shear rheometer, the discrete retardation time spectra were attained using the non2linear regression method. All viscoelastic functions are mathematically equivalent and belong to the same retardation time spectra, so the dynamic compliances of asphalt were converted to the static creep compliance using the retardation time spectra. Good correlations were found between calculation results and measurement results. In accordance to these findings, the retardation time spectra can accurately transform static and dynamic viscoelastic functions. Therefore, we can obtain viscoelastic properties over much larger time or frequency region than measurement results.

       Key words: viscoelastic properties of asphalt; retardation time spectra; non2linear regression; creep compliance; dynamic compliance