Effects of graphene oxide on early-age hydration and electrical resistivity of Portland cement paste

Abstract

The effects of graphene oxide (GO) on the early-age hydration process and mechanical properties of Portland cement paste were experimentally investigated in this study. Based on an isothermal calorimeter measurement, the hydration rate of cement was observed to increase with the increase of GO content by nucleation effect. On the other hand, the electrical resistivity development of GO-cement paste was monitored using a non-contact electrical resistivity device. The result showed that electrical the resistivity of GO-cement paste was evidently higher than that of plain cement paste. However, cement paste with excessive amounts of GO exhibited a decreased electrical resistivity due to the massive ion diffusion caused by GO. Compared to plain cement paste, the GO-cement paste exhibited obviously higher compressive and flexural strengths, but the enhancements in compressive strength began to decline when the GO amount was greater than 0.04%. The microstructure characterization indicated that GO can apparently densify the cement pastes with less

Strength Properties and Micro-structure of Steel Slag Based Hardened Cementitious Composite with Graphene Oxide

“…Secondly, the GO can decrease the flow when you compare the mixture A75G25 and A75G25GO. It is because of the large Ace* : pulverized RC-LFS replaced by 25% of α semi-hydrate gypsum aspect ratio and nucleation effect [1,23]. While the increasing flow of the mixture A100GO is because the increasing the air content by the GO.…”

“…Thus, the concrete with GO shows relatively better engineering performance. Finally, it's also believed that GO nanosheet can provide the crack-bridging effect which has a positive effect on crack resistance [1,2,23]. Base on the previous researches, GO can provide both physical reinforcement and chemical reinforcement at the same time.…”

“…The improvement can be summarized as four main reasons. First of all, the function group on the surface of graphene oxide provide high bonding strength between GO and hydrations (such as C-S-H and calcium hydroxide) of cement [1,2,23]. Secondly, as nanomaterial, GO can increase the load-transfer efficiency from cement matrix to the reinforcement [2].…”

“…Though reinforcing mechanism and reinforcing efficiency are different on case by case, there are special attention to the graphene oxide (GO). GO is mono-layer of 2-hybridized carbon atoms derived from a mixture of carboxyl, hydroxyl, and epoxy functionalities [1,2,3]. It has been reported by Z. Pan and K. Gong et al that carboxyl acid groups can react with calcium silicate hydrate (C-S-H) to form strong covalent bonds, thereby notably improving mechanical properties of GO-cement composites [4,5].…”

Study on the Dispersion of Graphene Oxide in Cement Composites

“…However, a high amount of GO in cement matrix does not necessarily give a better performance because excessive GO results in a loss of mechanical performance [5]. The dispersion and distribution of GO in cement pastes is essential to manipulate the properties of the resulting nano-composites.…”