Properties of carbon nanotube reinforced cement composite synthesized using different types of surfactants

Carbon nanotubes (CNTs) have proven to be the promising candidates to improve the tensile properties of cement composite. However, the properties depend upon the synthesis procedure which involves many parameters. In this study, investigations are carried out to determine the role of various sonication parameters, type of surfactant and dosage of CNT on compressive, tensile and fracture properties of CNT-cement composite. It is found that the CNT incorporated surfactant solution sonicated for a minimum of 1 h with the power of 70 W and the energy of 27 Ws/s provided the best dispersion. The dispersion capabilities of surfactants are found to be in the order of SLSD > SDB > GA > CTB > TX. It is also observed that the optimum dosage of CNT that can be incorporated into cement matrix is 0.06-0.1% by weight of cement. When CNTs are incorporated beyond that level, they cause detrimental effects to the cement matrix. Further, non-linear numerical scheme using loading-unloading history is proposed to determine the size-independent fracture energy of composite. The study demonstrates the role of synthesis procedure on the properties of CNT-cement composite and the procedure to numerically evaluate the performance of the composite. (C) 2017 Elsevier Ltd. All rights reserved.