Evaluation of Viscosity and Rutting Properties of Nanoclay-modified Asphalt Binders

摘要

In pavement constructions, asphalt binders are often modified with synthetic polymers to sustain excessive heat during hot summer days. However, the cost of a polymer-modified binder (PMB) is significantly higher than a neat binder. Nanoclays, on the other hand, are relatively inexpensive and naturally abundant, and have favorable intrinsic properties (e.g., nanoscopic size and surface area) toward increasing its stiffness. The current study evaluated viscoelastic properties of a performance grade (PG 64-22OK) binder modified with different dosages of Cloisite® 15A nanoclay. The state of dispersion and exfoliation of the nanoclay-binders were examined using Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) techniques. Preliminary results show that 1% and 2% of Cloisite® 15A increase the Superpave rutting factor of the base binder by 16% and 26%, respectively. The rotational viscosity (RV) tests reveal a significant increase in the viscosity of the base binder. The stiffness of the 2% nanoclay-modified binder was found to be about the same as that of a PMB-modified (PG 70-28OK) binder, indicating nanoclays can potentially be alternatives to PMBs toward reducing pavement construction and maintenance costs.