Understanding the behaviour of graphene oxide in Portland cement paste

Abstract

This study reports on the effect of graphene oxide (GO) on the hydration of Portland cement (PC) and industrial clinker. GO accelerates PC hydration, whereas it temporarily retards that of clinker. This difference reflects a twofold behaviour of GO in cement pastes. Retardation is due to the interaction of GO with the surface of hydrating grains, while acceleration results from a seeding effect. Gypsum causes this difference. GO is shown to have little effect on the strength of hardened pastes, and this merely relates to the change of hydration degree, as opposed to reinforcing effect formerly assumed. Overall, GO is not particularly active as a nucleation surface, as it aggregates and behaves in a similar way to inert fillers (e.g. quartz). Polycarboxylate-ether copolymer could make GO an active seed in cement pastes, as it prevents GO from aggregating. Nevertheless, this was found to occur only in alite pastes but not PC pastes.

Application of Graphene Oxide in Cementitious Composites for Cement Content Reduction

“…The overall acceleration on the hydration rate caused by GO occurs due to its elevated specific surface. GO is functionalized with carboxylate ions, serving as a nucleation site for the precipitation of silicate hydrates (GHAZIZADEH et al, 2018). Therefore, C-S-H nuclei may nucleate on the surface of GO nanoparticles, accelerating alite hydration and mechanical strength gain.…”

“…Colloidal silica may improve the rheological behavior of fresh concrete due to its high surface area (SENFF et al, 2009) and reduce its porosity due to its pozzolanic effect (RUPASINGHE et al, 2017). Graphene oxide may be used to increase concrete strength and durability because it acts as nucleation sites for the precipitation of C-S-H phases and accelerates its formation (GHAZIZADEH et al, 2018).…”

Effect of Graphene Oxide on the Mechanical Strength and Microstructure of Cementitious Materials

“…These results to great extent follow the same trend, with a peak, for the 7-day results, but with lower enhancement ratios compared to the benchmark specimen. This implies the stimulation effect of the GO for the hydration process at early ages [23]. It should be mentioned that the highest improvement in the counterpart group incorporating SF only was just 17% when 5 % SF replacement was used in specimen S5G0, while using GO alone had a limited improvement on the compression strength at 28 days.…”

Incorporação de óxido de grafeno em argamassa de revestimento: uma visão sustentável

“…As argamassas modificadas tiveram melhor resultado e enquanto a argamassa A teve um aumento de 3,7% em relação à argamassa de referência, a argamassa B teve aumento de 24,3%. Esse resultado contrapõe resultados de alguns pesquisadores, como e Ghazizadeh et al (2018), que constataram melhores resultados de argamassa com adição de óxido de grafeno em baixas dosagens de OG, entre 0,03% a 0,05%.…”