Interfacial heat transfer behavior of graphene-based filler and calcium-silicate-hydrate in cement composites

Abstract

Interfacial heat transfer behaviors between graphene-based filler and cement matrix play a pivotal role in controlling the overall thermal properties and functional performance. The mechanism of heat transfer in graphene-based nanomaterial and cement has not been well understood. In this work, the interfacial thermal conductance (ITC) of graphene /calcium-silicate-hydrate (C-S-H) and graphene oxide (GO) /C-S-H are investigated using molecular dynamics simulation, focusing on the degree of oxidation and type of oxygen functional groups (epoxy and hydroxyl). It is found that ITC increases monotonously with the increase of oxygen-concentration. Phonon analysis reveals the increasing oxygen-concentration will improve phonon transfer efficiency at the interface zone. The type of filler also effect on the ITC, that is, GO-hydroxyl > GO-epoxy > graphene. The interfacial phonon transmission coefficient of GO-hydroxyl /C-S-H is lower than that of GO-epoxy /C-S-H at the same oxygen-concentration. In addition, an analytical relationship between binding energy and ITC is proposed to prove that high oxygen-concentration GO can improve both mechanical and thermal properties of cement-based materials. This study is helpful for understanding the interfacial heat transfer behaviors of nanomaterials-cement composites and provides guidance for the design and control of their thermal properties.