Comparison analysis of dynamic modulus of asphalt mixture: indirect tension and uniaxial compression test

The dynamic modulus of asphalt mixture was one of the most essential parameters for predicting responses and performance of pavement structure in pavement design. The AASHTO 2002 Pavement Design Guide proposed a standard method to determine the dynamic modulus of the asphalt mixture under uniaxial compression test. However, many researchers in recent years have indicated that the dynamic modulus determined by uniaxial compression test could not be used for evaluation of existing pavement cores. Therefore, it is necessary to find an alternative method for dynamic modulus testing. The comparison study between two test methods of indirect tension and uniaxial compression was conducted in this paper. The measurement system of gage-point-mounted was adopted to determine the dynamic modulus of asphalt mixture under indirect tension using five types of asphalt mixtures with different binder types and nominal maximum aggregate size. The master curves of dynamic modulus and phase angle at a reference temperature of 20 degrees C were obtained according to the superposition principle of time and temperature. The results showed that there were distinct differences in dynamic modulus, phase angle, and shift factor of asphalt mixture measured using two test modes. The correlation relationship of the fitted formulas demonstrated a significant correlation between dynamic modulus under uniaxial compression and indirect tension.