Fly ash and slag

Cement based composite materials (CBCM) with superior mechanical strength and excellent durability are always desirable in practical applications. Although considerable research has been reported in the past decades about the use of Nano materials (NMs) for strength and durability enhancement of cement matrix, there is little information available on the use of graphene nano-sheets and their derivatives (GND) in cement-based materials. Particularly the role of GND in hydration processes and their mechanisms of strengthening in cement matrix are unclear. In this paper, a critical review on recent research findings about GND modified cement-based materials was conducted. The review mainly discussed the influence of GND on properties of cement matrix including microstructure, hydration, mechanical properties, etc. The information revealed in this paper would not only provide a comprehensive understanding of the effect of GND on cement composites, but also provide valuable ideas and guidance for similar studies in the future.

A critical review on research progress of graphene/cement based composites

Graphene-based nanosheets for stronger and more durable concrete: A review

Graphene oxide (GO) has been utilized to strengthen composite materials. In this study, the effects of GO on hydration degrees, macro-mechanical strength and calcium-silicate-hydrate (C-S-H) structure of cement based composites were investigated through comprehensive experimental tests. In addition, the aggregation mechanism of GO was verified by alkaline solution simulations, using Ca(OH)2 and NH3·H2O. Based on the experimental results, it was found that the 3-day and 7-day compressive strengths of cement based composites with 0.2 wt% of GO were increased by 35.7% and 42.3%, respectively as compared to the control. Moreover, the C-S-H structure of cement paste with GO was not observed to have undergone any change via qualitative and quantitative analyses combined with FT-IR, XRD and 29Si-NMR. Besides, the test results of TGA, DTG and 29Si-NMR showed that the hydrated degree of cement paste increased to 10.4% at 28 days when incorporating with 0.1% of GO.

Experimental study of the effects of graphene oxide on microstructure and properties of cement paste composite

Graphene oxide (GO) has attracted increasing interests for the use as nano-reinforcement in cement composites. However, the dispersion problem of GO nanosheets in alkaline cement matrix has been restricting its real application. In this paper, polycarboxylate superplasticizer (PC) modified GO (PC@GO) 1 was used to improve the dispersion of GO and the mechanical behavior of cement composites. The results show that PC@GO disperses uniformly in alkaline cement matrix and exhibits reinforcing effects on mechanical behavior of cement composites. With the addition of ∼0.242 wt% PC@GO (PC 0.22 wt%, GO 0.022 wt%) of cement, the compressive strength, flexural strength, Young's modulus and flexural toughness can be increased to 34.10%, 30.37%, 32.37% and 33%, respectively at early days. The toughening mechanism of PC@GO is attributed to its resistance to the formation and growth of cracks based on the characterization of cracks in scanning electron microscope images. This work has opened an effective way to use GO as a nano-reinforcing material for cement composites.

Qin Wang

Papers

Influence of graphene oxide additions on the microstructure and mechanical strength of cement

Effect of fly ash on rheological properties of graphene oxide cement paste

Rheological behavior of fresh cement pastes with a graphene oxide additive

Synthesis and properties of a silane and copolymer-modified graphene oxide for use as a water-reducing agent in cement pastes

Research progress on the effect of graphene oxide on the properties of cement-based composites