Ibrahim Amin¹, Sherif M. El-Badawy^1,, Tamer Breakah², Mourad H. Z. Ibrahim¹

The aim of this paper is to investigate the rheological properties of conventional asphalt modified with Multi- Walled Carbon Nano Tubes (MWCNTs). Pristine MWCNTs were chemically modified using acid functionalization process to introduce carboxylic acid groups onto the surface of MWCNTs. The pristine and functionalized MWCNTs were then characterized by Scanning Electron Microscope (SEM) and electron dispersion X-ray (EDX) analysis. A 3% (by weight of asphalt) of pristine and functionalized MWCNTs were each blended with a base asphalt at 120°C. The properties of the base and modified asphalts were evaluated using softening point, rotational viscometer and dynamic shear rheometer (DSR) for both original and short term aged asphalts using the rolling this film oven (RTFO) test. The results indicated that the use of MWCNTs as a modifier was helpful in improving the conventional and rheological properties of the asphalt. Generally, it was found that the softening point, as well as the rotational viscosity, were increased and the temperature susceptibility was improved. The results showed a remarkable improvement in the binder complex shear modulus, failure temperature, and rutting resistance. The rheological properties of the asphalt modified with pristine MWCNTs were better than the functionalized MWCNTs. Finally, the effect of mixing technique (high shear mixer and a manufactured mechanical mixer) of MWCNTs with asphalt was evaluated. Results showed that both mixers yielded similar properties based on the rotational viscosity testing.

CNTs, MWCNTs, DSR, RTFO, modified asphalt, rutting