Experimental prediction of the elastic properties of nanocomposite cementitious materials based on nanoindentation measurements

Abstract

This paper provides in depth novel exploration of the local mechanical properties of nanocomposite cement using the nanoindentation technique. The elastic properties of carbon nanotubes (CNTs)-reinforced and unreinforced cement pastes were first evaluated at the microscale level using nanoindentation. The grid indentation results for a representative microscale level area were used to predict the overall macroscale elastic properties by carrying out subsequent phase deconvolution and two-steps analytical homogenization using Mori-Tanaka scheme. Moreover, the elastic moduli (E) of cement pastes reinforced with various CNTs weight fractions were determined at the macroscale using static compressive tests. The nanoindentation results of various indents in the nanocomposite cement samples showed that randomly distributed E values can be measured at the interfacial transmission zone (ITZ) between the CNTs and the cement paste. The initial tangent E values of nanocomposite cement pastes, determined using the static compressive test, were higher than those of the cement matrix and lower than those of the CNTs. The experimental results of the static compression test were found to be in good agreement with those obtained by the homogenization of the nanoindentation results. The experimental results show significant increase in the E values of nanocomposite cement compared to those of unreinforced cement pastes. Finally, the experimental results obtained in this work were compared to previous computational and experimental findings reported in literature. 2017 by American Scientific Publishers All rights reserved.