Graphene-based modification on the interface in fibre reinforced cementitious composites for improving both strength and toughness

Application of Graphene in Fiber-Reinforced Cementitious Composites: A Review

“…Figure 9c shows that the electric conductivity was boosted more than one order from 5 × 10 −9 S/m for GO/PVA/cement to 10 −7 S/m for rGO1/PVA/cement. Moreover, in contrast to rGO1-based composite which experiences 1 min reduction, longer treatment time (1 h) for rGO2/PVA/cement composite gives a more significant enhancement of conductivity (4 × 10 −4 S/m), more than four orders higher than that of GO/PVA/cement sample [39]. Nevertheless, Uygunoglu et al [93] reported an opposite observation on the same material composition, despite using a different preparation method of GO/PVA fillers.…”

“…EPD process was finally conducted at 20 V for 1 h to coat GO on CF. To confirm the successful coating and characterize the surface morphology and functional groups of GO on fibers, various characterization techniques are adopted including scanning electron microscopy (SEM) imaging, atomic force microscopy (AFM) imaging, X-ray photoelectron spectroscopy (XPS) analysis, Raman spectroscopy, and Fourier Transform Infrared Spectroscopy (FTIR) [36,37,39]. Figure 2a shows the typical SEM image of GO-coated PVA fibers, where a relatively smooth GO film with distributed wrinkles can be observed.…”

“…Yao et al [39] performed single fiber pull-out test for GO-modified PVA fiber embedded in Ordinary Portland cement (OPC). By recording the maximum pull-out force (Figure 4e), the interfacial shear strength (IFSS) can be obtained based on known fiber diameter and embedded length [70,71].…”

“…Yao et al [39] carried out three-point bending tests to explore the effect of GO on the mechanical performance of PVA fiber-reinforced cementitious composites, as shown in Figure 6b. The incorporation of pristine PVA fibers in cement mortar can mildly increase its flexural strength by only ~5%.…”

“…With the GO modification, the splitting tensile strength of the 7-day samples further improves by 32.2% compared to the control group and such an enhancement rises to 41.2% after 35-days curing. Furthermore, based on the tensile stress-strain curves and starting from the theoretical model proposed by Li et al [68,69] as discussed in Section 4.1, Yao et al [39] estimated the tensile strength of PVA fiber/cement composites to be 6.18 MPa, which was increased to 7.83 MPa after introducing the GO coating. Meanwhile, an enhancement of toughness was deduced, from 2.94 to 33.16 kJ/m.…”