Improvement of repair mortars using multi-walled carbon nanotubes

The research reported in this paper focused on the improvement of repair mortars using multi-walled carbon nanotubes. Compressive strength, squeeze flow and flow-table tests were performed to assess the effects of incorporation of nanotubes on the rheological and strength properties of mortars. A reference mortar and five mortars with nanotubes were made, with nanotubes sourced from two different manufacturers. It was found that the cementitious composites were stiffer with higher nanotube content and that no more than 0·3% should be used to ensure mortar fluidity. Regarding the compressive strength, the results indicated that 0·3 and 0·4% of nanotubes increased the strength by 22 and 27%, respectively. However, 0·5% made the mortar difficult to mix and did not result in increased strength.