Figure 2.

(a) Various chemical methods have been employed to synthesize GO from graphite and subsequently exfoliate it, determining the C-to-O ratio in GO [11]. Adapted from Ref. [11]. Copyright 2020, Elsevier. The high surface area, porosity, and water absorption of GO contribute to a more compact composite material structure, thereby improving its mechanical properties. SEM micrographs were taken to observe the microstructure of the cement specimens, where (b) represented the specimens without GO and a w/c ratio of 0.35, and (c) represented the specimens with GO and a w/c ratio of 0.35 [29]. Adapted from Ref. [29]. Copyright 2019 Elsevier. GO serves as a catalyst for cement hydration products, thereby enhancing interfacial interactions among different substrates. SEM was used to observe the ITZ in (d) RFA mortar samples and (e) RFA mortar with GO samples at different magnifications after 7 days [30]. Adapted from Ref. [30]. Copyright 2018 Elsevier.