Lateral and longitudinal variations in dynamic modulus of asphalt pavement: Surface layer and base layer

The dynamic modulus of asphalt pavement is a significant factor used for predicting the pavement life. However, the service situations of asphalt pavement in lateral and longitudinal directions are different, which induces variation in the dynamic modulus of asphalt pavement. Given this background, this study aims to investigate the variations in dynamic modulus and phase angle in the longitudinal and lateral directions. Four road sections comprising surface layer and base layer were selected. For each road section, core samples were taken from three profiles along the longitudinal direction and four cores from different locations along the lateral direction were taken. The dynamic modulus and phase angle of specimen were characterised by indirect tensile test. The variations of dynamic modulus and phase angle in the lateral and longitudinal directions were analysed and compared with reference samples prepared in laboratory using master curve and coefficient of variation. The results show that the lateral and longitudinal differences induce more severe variations in dynamic modulus and phase angle compared with laboratory samples. Moreover, for the surface layer, the variation in the lateral direction is higher than in the longitudinal difference likely due to the inhomogeneity of asphalt mixture, variation in traffic loading, loading distribution, and the specific geometric structure of Norwegian pavement. In comparison with the surface layer, similar results caused by lateral and longitudinal differences are found for dynamic modulus and phase angle of the base layer because of its lower position and complicated stress distribution. Besides, a correlation between service life and the variations in dynamic modulus and phase angle is found for lateral samples.

Automated summary

This study aims to investigate the variations in dynamic modulus and phase angle in the longitudinal and lateral directions of asphalt pavement. Core samples were taken from four road sections and characterized by indirect tensile test. The results show that the lateral and longitudinal differences induce more severe variations in dynamic modulus and phase angle compared with laboratory samples. A correlation between service life and the variations in dynamic modulus and phase angle is found for lateral samples.