Effects of Organophilic Nanoclay on the Rheological Behavior and Performance Leading to Permanent Deformation of Asphalt Mixtures

Wheel track rutting is one of the most important issues associated with asphalt pavements. The considerable increase in highway traffic loads, notably in developing countries, has accelerated the appearance of this type of deformation. This defect leads to the accelerated degradation of the pavement and considerably reduces the level of road safety provided to the users. This paper presents the results of a study on the effects of organophilic nanoclay on the rheological behavior and performance to permanent deformation of asphalt mixtures. Two asphalt mixtures designed according to a standard methodology were investigated. A reference mixture was produced with a conventional asphalt binder and the other mixture with an asphalt nanocomposite prepared with nanoclay. The rheological evaluations were carried out on four-point fatigue test equipment under different load frequencies and test temperatures. For each test condition, the complex modulus ($|E^{*}|$) and phase angle ($\varphi$) were determined, along with the $|E^{*}|/\sin \varphi$ parameter associated with the permanent deformation behavior of the asphalt mixture. The resistance to permanent deformation was tested in a traffic simulator. The results obtained demonstrated an improvement in the rheological properties and resistance to permanent deformation of the asphalt mixture with the addition of organophilic nanoclay.