Evaluation of the effect of Slack wax and Polypropylene wax on the Rutting Properties of Rubber Modified Binder

The use of crumb rubber to modify the binders has been the interest of researchers for many years. It has been proven that the use of asphalt mixtures containing crumb rubber is leading to improve performance and increase the durability of asphalt pavement. However, increasing the viscosity of rubber modified binder which increases mixing and compaction temperature of asphalt mixture, known as one of the disadvantages of using crumb rubber. So, there is a good concept for using warm mix additives to besides improving the performance of asphalt mixture, reduce energy consumption and environmental pollution also be considered. On the other hand, binder has an important role in investigation of the performance of the asphalt mixture. It is also time-consuming and costly to evaluate the properties of asphalt mixtures. Evaluating the performance characteristics of the binder helps in understanding the performance of asphalt mixtures against various types of damage. The main objective of this study is to investigate the effect of organic warm mix additives (waxes) on the rutting performance of rubber modified binder by using the Multiple Creep Stress Recovery test. Because, it was found that the MCSR test results have a good correlation to rutting than SHRP criteria. The results of this study show that the use of polypropylene wax in addition to increase rutting resistance of rubber modified binder also will lead to increase in pavement traffic level by one degree. Despite of this, slack wax reduces rutting resistance of rubber binder by increasing the Jnr parameter.