Evaluation of Asphalt Binders Modified with Nanoclay and Nanosilica

During last decade, researchers' interest in nanotechnology applications, particularly in the field of pavement materials, has been increasing. This research work focused on the investigation of the properties of asphalt binder modified with different percentages of two different nanomaterials. These materials are nanoclay, and nanosilica. The nanosilica was manufactured from two different sources: silica fume and rice husk. Nanomaterials and asphalt binder were first characterized. A mechanical mixer was then used at 1500 rpm to mix the nanomaterials with the binder. Required mixing time was determined. Three different nanomaterial percentages were mixed with the binder. The modified binders were tested for rheological properties. Results showed that, nanosilica synthesized from silica fume tends to decrease the penetration value and increase the softening point temperature. The nanoclay on the other hand was found to increase the penetration and decrease the softening point temperature. At temperature of 135 degrees C and up to 150 degrees C, increasing nanosilica percentage was found to increase Brookfield Rotational Viscosity (RV), while nanoclay, at small percentages, increased the RV and then decreased it at higher percentages. At higher temperature, up to 165 degrees C, the RV values did not change significantly using both nanomodifiers. Nanosilica from rice husk showed improvement in the RV results. Finally, the Dynamic Shear Rheometer (DSR) results showed obvious improvement in the performance grade leading to higher resistance to permanent deformation.