Performance evaluation of bitumen with a homogeneous dispersion of carbon nanotubes

Nano-modified bitumen binders can be tailored to exhibit excellent properties for potential application in pavement engineering. However, a homogeneous dispersion of nano-materials in bitumen is still a challenge, which obscures the maximum property improvement of bitumen that can be achieved. In this study, a CNT sponge, which is a macroscopic assembly of nanotubes and represents one of the most promising lightweight carbon nanomaterials with homogeneous three-dimensional network and a high porosity, was used to reinforce bitumen. Bitumen can autonomously penetrate into the porous CNT sponge, and fill up all the pores, forming a bitumen/CNT nanocomposite with homogeneous CNT dispersion quality. We found that, the addition of CNTs significantly improves the performance of bitumen at elevated temperatures, as indicated by the much improved properties of stiffness, rutting resistance, creep and recovery behavior as well as high-temperature stability. Such effective modification of bitumen by CNT are ascribed to the highly uniform dispersion of CNTs, as well as the percolation structure formed throughout bitumen matrix. This study highlights the importance of CNT dispersion quality, and sheds light on the bitumen property improvement that could be achieved. (C) 2019 Published by Elsevier Ltd.