A recent review published in Nanomaterials analyzes the dispersion and reinforcement effects of graphene oxide (GO) in cement composites. The study focuses on the challenges of achieving uniform dispersion in the high-pH environment of cement slurries, its impact on macroscopic properties, and the mechanisms behind its reinforcement capabilities.
Study: A Review of the Impact of Graphene Oxide on Cement Composites. Image Credit: Robert Kneschke/Shutterstock.com
Challenges in GO Dispersion
Ensuring GO is evenly dispersed within cementitious materials is a significant challenge due to its oxygen-containing surface functional groups, which cause aggregation in porous solutions. This uneven dispersion limits GO’s effectiveness in reinforcing cement.
Surfactants and dispersants are used to improve GO distribution, but their effectiveness depends on their adsorption properties, which vary with pH. For example, surfactants like sodium dodecylbenzene sulfonate and Triton X-100 become unstable under alkaline conditions, reducing their effectiveness and impacting the mechanical properties of cement composites.
Polycarboxylate superplasticizers (PCE) have proven to be effective dispersants, enhancing GO distribution within cement matrices through steric hindrance and electrostatic repulsion. However, proper dosage is crucial. While low water-to-cement ratios require additional superplasticizers, excessive PCE can lead to over-fluidization, increasing segregation and bleeding risks.
Enhancing Cement Properties with GO
GO significantly improves the structural performance of cementitious composites when incorporated in optimal amounts. However, its effectiveness depends on multiple factors, including flake size, oxygen concentration, number of layers, type of cement, water-to-cement ratio, curing conditions, and preparation methods.
In addition to enhancing compressive, flexural, and tensile strength, GO improves other mechanical properties such as Young’s modulus, dynamic elastic modulus, deformation capacity, and toughness. It also enhances dynamic mechanical performance by reducing the loss factor, increasing the storage modulus, and improving energy absorption capabilities.
GO further enhances the durability of cementitious composites by mitigating carbonation, freeze-thaw damage, and calcium leaching while also obstructing the migration of harmful elements within the cement matrix. However, the underlying mechanisms behind these improvements require further in-depth study.
Mechanisms Behind GO Reinforcement
Microscopic studies suggest that GO enhances the strength and durability of cement composites through its exceptional mechanical properties, template effects, promotion of hydration product formation, and improved interfacial adhesion with the cementitious matrix.
GO nanosheets act as active centers for hydration phase growth, accelerating cement hydration and facilitating the formation of key products such as calcium silicate hydrate (C-S-H) gel, calcium hydroxide, ettringite, and monosulfate. These hydration products contribute to the evolution of cement microstructure and ultimately determine the hardened composite’s performance.
Nanoindentation studies indicate that GO-cement composites contain a lower proportion of low-density C-S-H and a higher concentration of high-density C-S-H compared to conventional cement composites. However, the precise microstructural changes induced by GO remain incompletely understood, necessitating further research.
Exploring Hybrid Nanomaterials
Researchers have also examined hybrid approaches that integrate GO with other nanomaterials to achieve synergistic reinforcement effects. For example, combining GO with nano-silica (NS) and functionalized carbon nanotubes (FCNTs) has shown promise in enhancing cement performance. This hybrid system leverages GO’s wrinkle resistance and dispersibility, NS’s pozzolanic reactivity, and FCNTs’ mechanical strength to significantly improve both mechanical properties and durability.
GO’s extensive surface area also allows it to function as an intermediary when combined with other materials, enabling multifunctional capabilities in cement composites. Integrating GO with various materials has demonstrated improvements in electrical conductivity, electromagnetic interference shielding, and thermal conductivity, expanding its potential applications in modern engineering.
Future advancements in integrating GO with other substances could lead to the development of intelligent cementitious materials with superior mechanical behavior, extended durability, and multifunctional potential for infrastructure and construction applications.
Future Outlook
GO continues to gain recognition as an effective nanoscale reinforcement for cement composites, thanks to its exceptional mechanical properties and unique surface functional groups. However, existing research contains inconsistencies and gaps that need to be addressed to fully understand its mechanisms and optimize its application in cement-based materials.
This review provides a comprehensive overview of GO’s role in enhancing cementitious materials. Moving forward, research should focus on refining dispersion methods, investigating GO-induced microstructural changes in cement hydration products, and analyzing its reinforcement mechanisms in various cement systems.
A deeper understanding of these factors will facilitate the development of next-generation intelligent, multifunctional cement composites tailored to the evolving needs of modern engineering and infrastructure. Additionally, innovative approaches, such as coating aggregates with ultra-thin GO layers, could further enhance the mechanical behavior and durability of cement-based composites.
Reference
Hu, Z.-Y. et al. (2025). A Review of the Impact of Graphene Oxide on Cement Composites. Nanomaterials, 15(3), 216. DOI: 10.3390/nano15030216, [https://www.mdpi.com/
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