The Effects of Graphene Oxide-Silica Nano-Hybrid Materials on the Rheological Properties, Mechanical Properties, and Microstructure of Cement-Based Materials

Abstract

Despite their excellent performance, two-dimension nanomaterials have certain limitations in improving the performance of cement-based materials due to their poor dispersity in the alkaline environment. This paper has synthesized a new two-dimension stacked GO-SiO2 (GOS) hybrid through the sol-gel method. Nano-SiO2 is coated on the surface of GO with wrinkling characteristics, and the atomic ratio of C, O, and Si in GOS is 1:1.69:0.57. The paper discusses the impacts on the spreading, Marsh cone flow time, rheological properties, mechanical properties, and microstructure of cement-based materials for the GOS at different mixing quantities. Furthermore, with the same mixing quantity of 0.01%, the influences on the dispersity, flow properties, rheological parameters, and mechanical properties of GOS and graphene oxide (GO) are compared. Lastly, fuzzy matrix analysis has been adopted to analyze the comprehensive performance of cement-based materials containing GOS. The research results indicate that, compared with the reference sample, the spreading for the GOS cement mortar with 0.01% mixing quantity was reduced by 4.76%, the yield shear stress increased by 37.43%, and the equivalent plastic viscosity was elevated by 2.62%. In terms of the 28 d cement pastes, the compressive and flexural strength were boosted by 27.17% and 42.86%, respectively. According to the optical observation, GOS shows better dispersion stability in the saturated calcium hydroxide solution and simulated pore solution than GO. Compared with the cement-based materials with the same mixing quantity (0.01%), GOS has higher spreading, lower shear yield stress, and higher compressive and flexural strength than GO. Finally, according to the results of fuzzy matrix analysis, when the concentration of GOS is 0.01%, it presents a more excellent comprehensive performance with the highest score. Among the performance indicators, the most significant improvement was in the flexural properties of cement-based materials, which increased from 8.6 MPa to 12.3 MPa on the 28 d.

Insights into the Mechanism of Graphene Acting on Water and Chloride Ion Permeability of Cement-Based Materials

“…Cement-based materials are the most widely used materials for construction projects. With the rapid development of the economy and the vigorous progression of urbanization, higher requirements are presented for cement-based materials, such as their mechanical performance and durability [ 1 , 2 , 3 , 4 , 5 ]. The hydration process of cement plays an important role in dictating the performance of cement-based materials.…”

The Investigation of Compacting Cement Systems for Studying the Fundamental Process of Cement Gel Formation

“…The study of the microstructure of calcium silicate hydrate (CSH) gels from theoretical and computational points of view, as well as the fractality of CSH and the evaluation of the mechanical properties and durability of CSH—with particular reference to carbonization and chloride/sulfate exposure—are also important in influencing the mechanical properties and durability of cement-based materials [ 30 , 31 ]. The most recent works of authors who studied the formation of the structure of cement pastes from the point of view of the mechanisms of gel formation and hardening are primarily aimed at the microstructural component of these processes and mechanisms [ 32 , 33 , 34 , 35 , 36 ]. Today, a large role is given to the study of the microstructure of cement pastes, in particular, microcracking [ 32 ], the characteristics of the pore structure [ 33 ], the effect of nanoadditives [ 34 ], and the mechanisms of carbonization and hydration, along with their products: calcium carbonate, aluminosilicate gel, and CSH phase [ 35 ].…”

“…The most recent works of authors who studied the formation of the structure of cement pastes from the point of view of the mechanisms of gel formation and hardening are primarily aimed at the microstructural component of these processes and mechanisms [ 32 , 33 , 34 , 35 , 36 ]. Today, a large role is given to the study of the microstructure of cement pastes, in particular, microcracking [ 32 ], the characteristics of the pore structure [ 33 ], the effect of nanoadditives [ 34 ], and the mechanisms of carbonization and hydration, along with their products: calcium carbonate, aluminosilicate gel, and CSH phase [ 35 ]. The study of these processes and mechanisms at the micro level contributes greatly to developing an understanding of the gel-type contributions to various materials that form next-generation concretes [ 36 ].…”