Laboratory Evaluation of the Effect of Nano Clay and Polymer on Rheological Behaviour of Binder and Rutting Performance of Stone Matrix Asphalt Mixtures

Permanent deformation or rutting is one of the most important distress modes that affect the life of flexible pavements. This type of distress is often observed on the roads that are situated in tropical regions. The properties of the constituent materials play a significant role in the construction properties of the pavement. The use of porous gradation and high binder grade for proper binding in the structure of mixes is known as the methods for improving the properties of mixtures. One of the mixtures made on this basis is Stone Matrix Asphalt mixtures (SMA). These mixes are a type of hot mixed with the coarse skeleton and the high binder and filler, which plays a key role, with the importance of the type and the tar properties used, as the binder of rock particles and the factor that has to endure the stress of the shear stress between aggregates.  On the other hand, due to the high percent of binder and the prevention of binder, the use of additives such as fibers or polymer materials is inevitable. The use of polymeric additives in addition to improving the binder properties, with the increase binder viscosity, also decreases binder drain down. Also, one of the recently applied additives to enhance the binder properties is Nano - clay. The aim of this study is to evaluate the effects of Nano clay as the main additive to binder to improve the binder properties alongside the SBS and fibers, in order to increase the loading resistance of asphalt and to correct its technical properties against the rutting. So, control asphalt mixtures containing of 60-70 binders with 0/4% fiber blended into mixture or modified bitumen mixed by 5 %, along with a montmorillonite additive of 1 %, 2 %, 3 % and 4 % for both pure and polymer bitumen. In this study, the Marshall test, dynamic creep tests and delamination were performed on different samples. The results of these experiments show improved performance of samples containing Nano - nanoparticles with an addition of Nano clay to 3%, which is best achieved performance in polymer modified mixtures.