Modeling the Influence of Nano Size Additives on the Creep Stiffness of Asphalt Binder

Abstract

Thermal cracking in asphalt concrete pavement represents a significant pavement distress in cold environment. As the temperature drops below freezing limit, thermal stress starts to increase in the restrained asphalt pavement layer. The flexural-creep stiffness of asphalt cement binder is measured with the aid of Bending Beam Rheometer (BBR at low temperatures. It is considered as a good indicator of the resistance to cracking of the binder at low temperature. An attempt has been made in the present study to evaluate and model the influence of Nano size additives (silica fumes and fumed silica) on the deterioration of the creep stiffness of asphalt cement binder of penetration grades (40-50) and (60-70). Conventional asphalt binders were found to be highly sensitive to stress at low temperatures. It was proved from the test results that the traditional Superpave criteria for characterizing low temperature cracking behavior of asphalt cement binders is not appropriate for conventional binders.