Modifying Cement Properties with Carbon Nanotubes: a Molecular Dynamics Study

Abstract

During the last few years, there have been an increasing number of research studies on compositesmade of cement and carbon nanotubes (CNTs). These nanostructures are long cylindrical molecules,made only of carbon atoms and can be described as rolled-up graphene layers and classified as singlewalled carbon nanotubes (SWCNTs) or multi-walled carbon nanotubes (MWCNTs) depending on thenumber of layers. Due to their excellent mechanical properties, they hold great promise as reinforcingmaterials in cement composites. In the present work, we used molecular dynamics simulations to modelthe pull-out of pristine and functionalized CNTs from a cement matrix (see figure 1). We estimated theinterfacial shear strength of the structures as a function of CNT length and degree of functionalization.Simulated results show that the interfacial shear strength increases with increasing the number offunctional groups due to the improvement of non-bonding interactions between the matrix and thecarbon nanotubes.