Effect of rGO on the mechanical strength, hydration and micromorphology of cement incorporated silica fume

Effects of TiO2-Modified RGO Composites on the Mechanical and Durability Properties of Ordinary Portland Cement Mortars

“…Furthermore, although TiO 2 –RGO or RGO addition led to elevated mechanical strength compared to the normal OPC mortars, the highest compressive and flexural strengths were obtained when the TiO 2 –RGO or RGO content was 0.03 wt %. Surprisingly, an excessive dosage of TiO 2 –RGO, 0.05 wt %, in this study resulted in reduced mechanical strength, which is in line with the findings from previous studies. − This could be because when used in excess, these composites may agglomerate to affect cement hydration, which are discussed based on subsequent SEM and XRD results. , …”

“…For example, it is noticed that the amount of portlandite (CH) in the specimen with 0.03 wt % of TiO 2 –RGO was obviously greater compared to the control without TiO 2 –RGO (as highlighted in blue dashed circle in Figure ), implying that TiO 2 –RGO facilitates the OPC hydration with formation of more crystalline phases in corresponding products. In fact, according to related literature, ,− both TiO 2 and RGO with a proper dosage level can accelerate the early hydration rate of OPC or promote the hydration degree of OPC. When comparing the sample with the TiO 2 –RGO to the one with RGO at the same content, it is noticed that the intensity of the peak assigned to portlandite was larger.…”

“…60−62 This could be because when used in excess, these composites may agglomerate to affect cement hydration, which are discussed based on subsequent SEM and XRD results. 63,64 Compared to the normal RGO, which is prone to agglomeration and stratification, TiO 2 −RGO has a relatively better dispersibility and does not tend to aggregate in the OPC pore solution. Therefore, during the mixing of OPC mortars, the TiO 2 −RGO composite could disperse more evenly in the OPC slurry with water and further improve the mechanical strength of mortar specimens later.…”

A minireview on the utilization of petroleum coke as a precursor for carbon-based nanomaterials (CNMs): perspectives and potential applications

“…Reduced graphene oxide (RGO) is a 2D nanomaterial prepared by chemically oxidizing natural graphite to obtain graphene oxide, and then reducing it to the point of producing a material with a low content of oxygen functional groups present in the basal plane of graphite. As such, RGO has attracted research attention due to its intrinsic properties that are similar to those of graphene, such as biocompatibility, 155 high mechanical resistance, 156 high surface-to-volume ratio, 157 and high thermal and electrical conductivities. 158 Furthermore, the oxidation and hydrothermal methods of GO to generate RGO are less expensive than the current methods of graphene synthesis, which are quite expensive and of low yield, such as mechanical exfoliation and CVD.…”

May the Piezoresistivity of GNP-Modified Cement Mortar Be Related to Its Fractal Structure?

“…Compared with GO, that is widely used to enhance the mechanical properties of CBMs due to its stronger surface actions [12][13][14], GNPs that are composed of several layers of graphene with the diameter of several microns and thickness of less than 100 nanometers shows benefits to enhance the electrical properties of CBMs owing to its high electrical conductivity [15]. The improvement in the mechanical properties of CBMs by GBNFs is generally attributed to the enhanced cement hydration, tightly packed, and uniformly distributed hydration crystals, and decreased or eliminated cracks and flaws of the material matrix [16]. However, these effects may be counterbalanced by the raised flaws of the agglomerations of GBNFs, so strength may decrease at high GBNF dosages [17,18].…”