Molecular Dynamics Simulation and Durability Experiment on Functional GO-Modified Cementitious Composites

Abstract

Microscopic characterization and macroscopic specific experiments are combined to explore the influence of functional graphene oxide (GO) on cementitious composites performance. The simulation through molecular dynamics (MD) characterizes the adsorption at the GO/C–S–H interface by analyzing the adsorption energy, radial distribution function (RDF), mean square displacement (MSD) and time correlation function (TCF), and the adsorption morphology of GO by radius of gyration (Rg) and concentration profile, reflecting the interface contact area used to further characterize interfacial bonding. The mechanical properties of mortar were tested, scanning electron microscopy (SEM) observed the mortar interface, and energy dispersive spectroscopy (EDS) calculated the ratio of Ca/Si. The durability of mortar was characterized, showing that the adsorption capacity of GO/C–S–H interface is: GO-C > GO-O > GO-N > GO-S. The GO-C has the strongest adsorption effect, and the interface adsorption effect of GO-S is the weakest. When the functionalized GO incorporation is 0.1%, GO-C can significantly improve the mechanical properties and durability of mortar. The enhancements of GO-O and GO-N are secondary, while GO-S showed the least improvement.