Soot-Derived Flash Graphene as Cement Additive

The incorporation of graphene-based materials into cement composites is one of many interesting nano-reinforcement techniques. However, the conventional production of graphene materials usually requires large quantities of solvent with energy-intensive mixing, which in turn restricts their commercial viability in cement and concrete applications. In this study, an approach for production of flash graphene (FG) from motor oil soot and diesel particulate using a Joule heating system was developed. A high-quality FG was obtained, as evident from Raman spectroscopy analysis. The FG product was added to a mixture to reinforce its microstructure. The results of the mechanical tests conducted on the cement mortar reinforced by admixing 0.1 wt % FG showed an increase in compressive, tensile, and flexural strengths and modulus of elasticity by 38%, 27%, 27%, and 34%, respectively, after curing for 28 days. The durability characteristics in terms of water absorption showed a slightly higher resistance of the FG-reinforced mortar to water penetration. The drying shrinkage of the FG-reinforced mortar was like that of the control mixture. A molecular dynamics simulation was performed on the cured FG-reinforced cement mortar to find that the Ca-Si interactions in the hydrated cement phase were boosted by the presence of FG, in addition to the strong interaction between the Ca and FG sheets. This study could contribute toward developing strong and sustainable nano-reinforced cementitious composites using graphene materials derived from inexpensive carbon and waste sources.