Materials Genome for Graphene-Cement Nanocomposites

Graphene nanoplatelets have unique mechanical, thermal, and electrical properties that render them ideal reinforcing materials. The attractive properties of graphene have led to intensive research on graphene-polymer nanocomposites. However, very little work has been reported on using graphene in manufacturing multifunctional cement-based nanocomposites. This paper attempts to bridge recent findings of science-based discovery and nanoscience to the ancient and challenging technology of cement. Utilizing a holistic approach (i.e., integrating modeling, synthesis, and analysis of cement) is a challenge that cannot be fully addressed in one paper or one research experiment. Therefore, this paper presents a general framework for using a system approach to study cement-based materials. The paper highlights primary findings in manufacturing and characterizing graphene-cement nanocomposites (GCNCs). A bottom-up approach is used to correlate the atomic assembly of GCNCs with their macroscopic properties. At the atomic level, X-ray diffraction is used to predict the chemical composition and crystallography of GCNCs. At a nanoscale level, atomic force microscopy (AFM) is used to examine the physical and chemical properties of GCNCs. Molecular dynamics (MD) analysis is conducted to estimate the interfacial strength between calcium silicate hydrate (C-S-H) and the graphene nanoplatelets functionalized with different chemical groups. At a microscale level, scanning electron microscopy (SEM) is used to obtain information about surface topography and the composition of GCNCs. At a mesoscale level, mechanical properties are measured using resonant ultrasound spectroscopy (RUS). This multiscale evaluation showed a strong correlation between the morphology and performance of GCNCs. Functionalizing graphene nanoplatelets tends to improve interfacial strength, which tends to improve the overall mechanical properties. (C) 2013 American Society of Civil Engineers.