Contribution of the Bituminous Mortar and Stone Skeleton to the Resistance to Permanent Deformation in Asphalt Mixtures

This paper describes the results of a research that was conducted to investigate the contribution of the different components in an asphalt mixture to the resistance to permanent deformation. As part of this research, extensive triaxial tests were performed on the stone skeletons of dense, stone mastic, and porous asphalt concrete. An extensive characterization of the bituminous mortar was also performed using the dynamic shear rheometer and the direct tension tests. The results showed that aggregate skeletons exhibit a high tendency to dilate implying tensile stresses and strains in the bituminous mortar. The results also showed that plastic deformation is much more important than viscous deformation for the stone skeleton mixtures and that viscous deformation is more important for the dense mixture. The findings of the research were used to analyze the permanent deformation that occurred in accelerated pavement test sections.