Assessment of the Influence of Nano Metakaolin filler on Asphalt Binder Rheological Properties

Abstract

This paper investigates the effects of using nano metakaolin filler on the rheological properties of asphalt binder. In this work, asphalt binder of penetration grade 60 to 70 was prepared at three percentages (1%, 3%, and 5%) of asphalt weight using a high shear mixer fixed at 4,000 rpm for 60 min. Evaluations were then made of the properties of the modified asphalt binder such as the rotational viscosity, penetration grade, softening point temperature, temperature susceptibility, and ductility. The results of this work showed that the use of nano metakaolin filler as a modifier was helpful in improving asphalt binder properties. In general, it was found that the viscosity and softening point values increased, while the penetration value and temperature susceptibility (P.I.) values were reduced. The high shear mixing allowed good diffusion of nMK fillers into the asphalt binder, producing a homogenous composite binder. Additionally, the results showed that 5% nano metakaolin by asphalt weight was a reasonable additive to develop the rheological properties, increasing the softening point and viscosity values by about 14 and 77%, respectively while developing higher percentages of reduction in penetration value and ductility value of about 30 and 18%, respectively, making this more applicable to the construction of highway pavements in hot weather conditions.