Laboratory evaluation of dynamic performance and viscosity improvement in modified bitumen by combining nanomaterials and polymer

One of the most common forms of failure in pavement performance is rutting. Bitumen can play a decisive role as one of the main materials used in asphalt mixtures, and modifying the properties of bitumen can greatly delay these failures and minimizing them in some cases. The current study aimed at modifying polymer bitumen with a combination of nano-clay and nano-lime. The PG 58-16 bitumen was modified by nano-clay and nano-lime. In this study we have 3 samples with different percentages of nano materials. The effect of this modifier on reducing rutting failure was evaluated compared to the control sample. Our control sample is modified bitumen with 3% weight percentage of Styrene-Butadiene-Styrene (SBS). The Rotational Viscometer (RV) tests were performed to determine the viscosity parameter. At a constant temperature, the addition of nanomaterials to the polymer bitumen increased the viscosity and the stiffness of bitumen was accordingly modified. The rutting parameters including non-recoverable creep compliance (Jnr) and the recovered creep (R%) were also evaluated, and then the effect of nano-silica on the improvement of these parameters at high temperatures was evaluated by simulating dynamic loading using Dynamic Shear Rheometer (DSR) and performing the MSCR test at 3 temperatures of 58, 64 and 70 degrees C. Also, the effect of nano-clay and nano-lime hybrid on rutting parameters was evaluated in two nonlinear and linear viscoelastic states. The results showed that the addition of modifiers to polymer bitumen, due to the increase in viscosity, resulted in stiffness of the bitumen and improvement of the rutting parameters at zero shear viscosity (ZSV). In all three experiments, the effect of nano-lime was significantly higher than that of nano-clay on increased resistance to rutting in this study. (C) 2019 Elsevier Ltd. All rights reserved.