Investigating the effect of nano-silica on the specification of the sasobit warm mix asphalt

Abstract

In this investigation, Nano-silica has been added in three percentages of 2%, 4% and 6% to improve the physical, rheological and mechanical properties of warm mix asphalt (WMA) containing 2% Sasobit. Several experiments have been conducted to evaluate and characterize the prepared samples. The results of investigations indicated that by increasing the percentage of Nano-silica, the qualification and functionality of the warm mix asphalt has been improved. Resilient modulus of WMA was slightly increased by increasing the Nano-silica content. So, the response of pavement to traffic loading at 25oC has been improved. Depth of cracking at a specified load cycles was decreased dramatically by adding the Nano-silica to the Sasobit WMA. At the same time, the stiffness of modified samples was much lower than control WMA. As a result, the Nano-silica extends the fatigue life of asphalt concrete. In addition, the wheel tracking test results depicted that the rutting depth have been reduced by increasing the Nano-silica content. Regarding the results of qualification tests, 4 wt% of Nano-silica was selected as the optimum content.