Investigating the creep properties of asphaltic concrete containing nano-silica

This study was aimed at investigating the creep behaviour of a typical asphalt concrete containing different percentages of nano-silica. The penetration grade of 60/70 asphalt cement was modified with different percentages of nano-silica (i.e., 1, 3 and 5%, by the weight) and was used for making the asphalt concrete specimens. The asphalt concrete specimens were subjected to dynamic creep tests. Dynamic creep tests were conducted at different stress levels and temperatures. A three-stage model, developed was fitted to the dynamic creep test results to capture the primary, secondary and the tertiary creep regions, and calculate the flow number and the steady-state strain rate in the secondary creep region. The results showed that, the flow number increased, and the steady-state strain rate decreased with increasing nano-silica content, indicating the increase of resistance against permanent deformation.