Investigation on the Effect of Addition of Nano Alumina, Nano Silica, Nano Titania, and MWCNTs on Flexural and Compressive Strengths of Cement Mortar

Being at the threshold of a revolution in nanotechnology, new advanced materials with higher knowledge contents, new functionalities, and improved performances are increasingly critical for industrial competitiveness and sustainable development. The current experimental research would focus on developing a new cement mortar material by partial replacement of cement with nanoparticles. Special concentration on controlling and presenting cement mortar flow rate according to ASTM C 1437, and also a comparison of mechanical performances of three Nanopowder and the Nanotube materials, could be considered as a distinctive and innovative part of this research. Such nanomaterials are the most useful ones with the most integrating effects. In this investigation, 60 prism specimens in four series each consisting of four specimens with nanomaterials and one benchmark, were prepared and molded-in triple-gang molds. Bending and compressive tests were conducted on the specimens at the age of 7, 28, and 90 days according to ASTM C348 and 349 standards. The results depicted that the best performances of investigated nanoparticles in increasing flexural and compressive strengths would occur in the early 7 days. Also, the diagrams indicated that specimens with 4% nano-silica provided up to 61% growth in 7 days compressive strength and 34% growth in 7 days flexural strength in comparison to average strengths of benchmark specimens. Thus, it can be recommended as the optimum mixing percentage of nanoparticles. Also, multi-walled carbon nanotubes, MWCNTs, showed acceptable performance in increasing the strength. Nano titania and nano alumina exhibited approximately neutral or negative effects on flexural and compressive strengths. The most important challenge in this study would be a dramatic decrease in the activity of nanoparticles in ages between 7 and 90 days.