Optimum content of nano-silica to ensure proper performance of an asphalt binder

Abstract

There is a growing need to improve the performance properties of asphalt binders in order to minimise the occurrence of failure mechanisms such as permanent deformation, fatigue, adhesiveness and moisture damage. Nano-structured materials have taken a scientific-industrial boom as asphalt modifiers due to their mechanical, thermal and electrical properties, among others. The chemistry of the nano-material, and thus their inherent physical properties, ends up with each one having specific effects on the asphalt and variable blending forms depending on their nature. This paper evaluates the effect of the incorporation of nano-silica (nano-SiO2) into a PG64-22 binder at various contents from 0.5% to 6.0%. Nano-SiO2 is widely used in the painting industry to improve adhesion of the paint to walls and provides an impermeable coat. Morphological, rheological and thermal analysis techniques were used to quantify the effect of asphalt binder modification. Such techniques were differential scanning calorimetry, thermogravimetric analysis, as well as Fourier transform infrared spectroscopy and atomic force microscopy. Selection of the optimum modifier content was mainly based on dynamic shear rheometry asphalt fatigue and rutting tests and work of adhesion analysis.