International Journal of Nano Dimension (Int. J. Nano Dimens.) Increasing flexural strength and toughness of cement mortar using multi-walled Carbon nanotubes Volume 5 (2014) Issue 4, October 2014 2024 02 29 Increasing flexural strength and toughness of cement mortar using multi-walled Carbon nanotubes 10.7508/ijnd.2014.04.012 EN J. Esmaeili Assistant Professor, Department of Structural Engineering, School of Civil Engineering, University of Tabriz, Tabriz, Iran. A. R. Mohammadjafari Ph.D. Student, Department of Structural Engineering, School of Civil Engineering, University of Tabriz, Tabriz, Iran. Journal Article 2024 02 29 In this study the effect of using multi-walled carbon nanotube (MWCNT) on flexural and compressive strengths, ultimate displacement and energy absorption capability of standard cement mortar considering different weight percentages of nanotubes as well as different dispersion methods has been investigated. Influential point in adding nanotubes to the composites is their proper dispersion, which is considered by comparing the results of two different dispersion methods. According to the test results and scanning electron microscope (SEM) images, the method using functionalized MWCNTs together with ultrasonication is pointed as an appropriate dispersion method. Using nanotubes resulted in significantly increase in the flexural strength and specially toughness of cement mortar which represents the ability of properly dispersed nanotubes in bridging and closure of the micro cracks. Finally, the observed results has been assessed with a statistical analysis and validated with acceptable significance levels.