Mechanical and durability performance of carbon nanotubes (CNTs) and nanosilica (NS) admixed cement mortar

For many decades, investigations for improving the behaviour of conventional cementitious composites both in terms of strength and durability is continuously carried out by adding various nanomaterials, replacing some amount of cement with different nanomaterials. Nanotechnology or Nanoscience is one of the most promising areas trending these days for studying enhanced properties of cementitious com-posites and is almost touching every field of study like medicine, environment, petroleum industry, etc. In Civil Engineering, the addition of nanomaterial in the cementitious matrix leads to enhanced mechanical properties like flexural strength, compressive strength, Young's modulus, etc., as well as improved dura-bility properties. In the present study, mortars incorporating NS (1% by cement weight) and MWCNTs (0.3% by cement weight) of 4 different types, i.e., functionalized and un-functionalized with two different diameters (10-20 nm and 30-50 nm), were prepared for assessing mechanical and durability properties at 28, 56, 90 and 120 days. Compressive and flexural strength was enhanced for nano admixed mortar than control samples (CS). Also, the nano admixed mortar was proved to be excellent in resisting sulphate attack and abrasion. Ultrasonic pulse velocity (UPV) results showed good quality for nano admixed mor-tar samples. In all the study cases, the mortar sample prepared with treated MWCNTs and having a diam-eter of 30 nm-50 nm (T2) performed better than CS and other nano admixed mortar. Microstructure images strongly correlated with the experimental results. (C) 2020 Elsevier Ltd. All rights reserved.