The effects of adding nano clay and nano zinc oxide on asphalt cement rheology

This study aims at investigating the effects on asphalt cement (AC) rheology when adding Nano Clay (NC) and Nano Zinc Oxide (NZnO) compounds. The tested contents of NC were 8%, 10%, and 12%, while those of NZnO were 1%, 2%, and 3% by weight of the AC. The study used AC of 60/70 penetration grade since it is the most commonly used in the Middle East region. Different tests were performed on both the control AC (CAC) and modified AC (MAC), including dynamic shear rheometer (DSR), Softening point (SP), penetration, flash and fire points (FFP), bending beam rheometer (BBR), and viscosity tests. These tests' results demonstrated that the modifiers tend to decrease the penetration values but increase the FFP, viscosity, and SP values. A slight improvement in the rheological properties of AC at high temperatures was also evident from the addition of NC or NZnO. Furthermore, adding either modifier led to significant improvements at low-temperature conditions in the AC's performance and cracking resistance. The optimum modifiers of NC and NZnO were 10% and 3% by weight of the AC, respectively.