AbstractThe use of multi-walled carbon nanotubes (MWC-NTs), as excellent mechanical and conductive fibers, for making self-sensing cementitious composites has attracted great interest. However, few researches have focused on the durability of mortar with MWCNTs. This paper attempts to explore the corrosion of embedded steel rebar in cement mortar with different contents of MWC-NTs. Tests for compressive strength, chloride migration coefficient, conductivity, and corrosion behaviors of MWCNT-cement mortar were carried out. The results show that the addition of MWCNTs to the cement mortar accelerated the development of the steel corrosion under chloride environment. The migration behavior of chlorine ions and steel corrosion rate were related to the carbon nanotube content. The increase in carbon nanotube content resulted in higher steel corrosion intensities. Moreover, the rates of chloride transport into the mortar increased with the nanotube content under both accelerated and natural chloride conditions.