Performance Evaluation of SMA Mixtures Modified by Nanoclay

Abstract Fatigue cracking and permanent deformation are two major distresses that occur in asphalt pavements. Several studies in that past have indicated that utilization of nanomaterials, especially nanoclays, has a significant influence on enhancing the performance of pavement. Therefore, the aim of the current paper is to evaluate the influence of montmorillonite nanoclay on intermediate and high-temperature performance of an original binder and mixture modified by styrene-butadiene-styrene (SBS). Different percentages of nanoclay were added to the original binder (1, 2, 3 and 4 % by the weight of the binder). The fatigue and rutting behavior of binders were evaluated through linear amplitude sweep and multiple stress creep recovery (MSCR) tests. To investigate the performance of mixtures, several mixture tests were implemented, such as static and dynamic creep, wheel track, and four-point beam fatigue tests. The results of the MSCR test revealed that the addition of nanoclay and polymer improves the rutting resistance of the binder, and among modified binders, binder modified with 4 % nanoclay and 5 % SBS has the lowest Jnr and highest percent recovery value. Based on the mixture performance tests results, by the addition of nanoclay, the fatigue and rutting resistance of mixtures increased up to 3 %, and by the addition of more nanoclay, a decreasing trend was observed.