Permanent deformation performance under moisture effect of an asphalt mixture modified by calcium carbonate nanoparticles

This study aimed to reinforce the nanostructure of a polymeric asphalt binder with the incorporation of nanoCaCO3, focusing to increase the resistance to permanent deformation and reduce moisture damage in the asphalt mixture. The experimental procedure consisted of developing asphalt nanocomposites with nano-CaCO3 incorporation of 2%, 4%, 6%, 8% and 10% by weight of the binder, seeking to obtain an optimal addition content. Thus, a nanocomposite with 5.5% nano-CaCO3 was defined based on high temperature rheological parameters. Subsequently, two asphalt mixtures have been formulated: a reference mixture and another nanomodified in the selected content. The evaluation of the resistance to permanent deformation and moisture damage in the asphalt mixtures occurred through the French Ornie ' reur equipment (traffic simulator). Therefore, two situations were investigated: the first with unconditioned asphalt slabs (control condition) and the second with conditioned asphalt slabs (saturation, freezing and water bath). The results obtained showed that the nano-CaCO3 incorporation enhanced the wettability and improved the rheological parameters related to high temperatures performance of the polymeric asphalt binder. Finally, it was found that the use of the nanocomposite with 5.5% nanoCaCO3 in the formulation of the asphalt mixture was able to reduce the emergence of permanent deformations in the control situation (37% reduction) and in the conditioning situation (47% reduction). Therefore, it can be concluded that the incorporation of 5.5% nano-CaCO3 to the asphalt matrix improved the interaction between the binder and the aggregate, in addition to the rheological behavior of the binder. These improvements resulted in an asphalt mixture with high performance to permanent deformation and less susceptibility to moisture damage.