Effect of dispersibility of carbon nanotubes by silica fume on material properties of cement mortars: Hydration, pore structure, mechanical properties, self-desiccation, and autogenous shrinkage

Abstract

In this study, the effect of dispersibility of carbon nanotubes (CNTs) by silica fume on the material properties of cement mortars were experimentally analyzed. Cement mortar specimens incorporating different proportions of silica fume and CNTs were fabricated, and tests were conducted to measure their hydration kinetics, pore structure, compressive strength, elastic modulus, internal relative humidity, and autogenous shrinkage. Additionally, scanning electron microscopy analysis was performed to observe the morphology of the CNTs in the cement matrix. The results revealed that the dispersibility of the CNTs was enhanced with the increasing replacement ratio of silica fume. Furthermore, well-dispersed CNTs resulted in a decrease in the self-desiccation by varying the pore structure and hydration kinetics, and an increase in the modulus of elasticity, thereby reducing the autogenous shrinkage of the cement mortar specimens. © 2020 Elsevier Ltd