Use of Nanoclays as Alternatives of Polymers Toward Improving Performance of Asphalt Binders

The main goal of this study is to assess the feasibility of the use of nanoclay as an alternative to commonly used polymers such as styrene-butadiene-styrene (SBS), which are used to modify the performance grade (PG) of asphalt binders. Three types of nanoclay and two types of neat binders were selected for laboratory investigation. Different amounts (1, 2, and 3%) of nanoclays were used. A blending protocol has been developed to mix the nanoclay with the asphalt binder. Rotational Viscosity (RV), Dynamic Shear Rheometer (DSR), Optical Contact Analyzer (OCA) and Atomic Force Microscope (AFM) were conducted to evaluate the properties of modified asphalt binders. Significant increases of viscosity and complex shear modulus were observed for nanoclay-modified binders because of nanoclay’s nanoscale phenomena such as structural features, quantum effects, spatial confinement, high surface energy, and a large fraction of surface atoms. The maximum rutting resistance is expected for binders modified with the 1% Cloisite 11B. The OCA test results suggest that the modified asphalt binders possess higher surface free energy than the neat binder. Therefore, cohesive energy which is an indicator of moisture damage was increased for modified binders. From the AFM analysis, adhesion and deformation values decreased for modified asphalt binders. The minimum adhesion and deformation values were found for asphalt binder samples modified with the 1% Cloisite 10A