Viscosity prediction model of natural rubber-modified asphalt at high temperatures

Viscosity is a physical indicator of the flow behavior of asphalt at high temperatures, and the mixing and compaction quality of asphalt mixtures depends on it; however, previous studies cannot effectively guide the application of natural rubber-modified asphalt (NRMA). In this investigation, the effects of the natural rubber latex (NRL) dose, test temperature and shear rate on the apparent viscosity of NRMA were evaluated. The results show that viscosity is approximately positively correlated with NRL dose, as described by an exponential equation that is based on Einstein's equation. Meanwhile, viscosity is negatively correlated with test temperature and shear rate, in accordance with the Arrhenius equation and power law equation, respectively. A three-factor physical equation was established to describe the relationship between viscosity and NRL dose, temperature and shear rate on the basis of the equations above, which can predict the viscosity over a wider range with limited experimental data, thereby overcoming experimental limitations. This study provides a prediction model for quickly determining the viscosity. This model is not only applicable to NRMA but also can provide references for the study of viscosity prediction for other polymer-modified asphalts.