# On the Stability of Graphene-Based Aqueous Dispersions and Their Performance in Cement Mortar
## 5 Conclusions  
In the present study Gr-TG, Gr-SG and GO were used to manufacture cement mortars. The graphene-based nanomaterials were added up to 1.0% by weight of cement. For the first time, to the best of our knowledge, a novel, robust, affordable technique, the static multiple light scattering (SMLS), was proposed and used to assess the stability of the dispersion of the graphene-based nanomaterials. The results showed that the most efficient pre-treatment to improve both dispersion stabilization and exfoliation, among those  
Figure 10: FESEM images of Gr-TG and GO flakes within 1 TG and 1 GO specimen fragments: (**a**) agglomeration of Gr-TG flakes; (**b**) zoom-up of the region in the red ellipses; (**c**) agglomeration of GO flakes; (**d**) isolated GO flake within the matrix, taken in scanning mode. Figure 9: FESEM images in back-scattering mode of Gr-TG and GO flakes within 1 TG and 1 GO specimen fragments: (**a**) Gr-TG flake halting the crack’s propagation; (**b**) Gr-TG flake filling a circular pore created by an air void; (**d**,**e**) GO flakes at different length scale. Examples of EDX spectra of (**c**) Gr-TG and (**f**) GO flakes of highlighted regions (red boxes) of doped cement mortar fragments. analyzed, is the two-step process, characterized by an initial hydrothermal treatment aided by sodium cholate, followed by sonication. As expected, a decrease in workability was measured with the increase of carbon nanomaterials, more marked with the addition of Gr-SG. It can be ascribed to its higher SSA. Despite the increased stability of the dispersions, only a limited increase in the compressive strength of mortars was observed with the addition of 0.3 wt% of Gr-TG and 0.3 wt% of Gr-SG, around 15% and 12%, respectively. The highest dosages of graphene-based nanomaterials do not further improve the mechanical properties. Specifically, at those concentrations, carbon nanomaterials form isolated flakes and clusters, characterized by overlapped layers with no evidence of cement hydration products among them. As a consequence, they are prone to promptly ungroup or slide over each other when stresses are applied around the clusters. A reduction in capillary water absorption of approximately 20% was measured for a Gr-TG concentration of 1.0 wt%, which can be attributed to the refinement of porosity caused by carbon nanomaterials. The outcome of the present investigation allows us to highlight the areas where further research is needed to fully exploit the properties of the carbon-based nanomaterials in cement mortars. Not only is it required to ensure their stable dispersion in water, but it is also crucial to provide efficient routes to increase their degree of exfoliation and functionalize them to improve their interlocking with the cementitious matrix. T.G. : Writing the draft, data curation. S.B. : Performed \(N_{2}\) measurements and porosimetries data curation. C.P.B., A.P. and R.G.A. : Performed \(N_{2}\) measurements and review. M.M. and A.T.: Performed MIP measurements and review. M.D. : Performed FESEM analyses and review. A.S. and L.S.C. : Performed Raman analyses and review. S.C. and D.P. : Designed this study, supervision, writing--review and editing. All authors have read and agreed to the published version of the manuscript. Part of this work was funded by Italian Ministry of University and Research, project \"STAR2--PIR-00008\". Not applicable. The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author. The authors declare no conflicts of interest. The following abbreviations are used in this manuscript: