Effect of carbon nanotubes sonication on mechanical properties of cement pastes

Abstract The excellent mechanical properties of carbon nanotubes (CNTs) make them a highly attractive material for use as reinforcement in cement composites. However, it is established that this nanomaterial presents a severe dispersion problem in cement matrices owing to its high specific surface area. An alternative method for dispersing the CNTs is the use of sonication in the presence of a superplasticizer admixture. However, high energy sonication can severely damage CNTs, which can affect their behavior in cement pastes. Thus, it is necessary to optimize the CNTs sonication parameters to optimize the performance of CNT-cement pastes. After sonication with different energies of CNTs water suspensions, the CNTs dispersion was evaluated through UV-Vis spectroscopy and the eventual CNTs damage observed by TEM. Workability, compressive and flexural strengths of the CNTs-cement pastes were also measured. The results revealed that the sonication parameters can be optimized to enhance the effect of CNTs on cement paste behavior.