Compressive strength sensitivity of cement mortar using rice husk-derived graphene with a high specific surface area

•Graphene-like materials (GRH) with high SSA were synthesized from rice husks.•GRH mortar, with a higher SSA, showed a better compressive strength.•Large edges in GRH may provide a better bonding environment with cement molecules.

Herein, we demonstrate improvements to the compressive strength of cementitious mortar by incorporating rice husk-derived graphenes (GRHs). Several manufacturing trials were undertaken to synthesize optimized GRHs using different dosages of rice husk ash and potassium hydroxide as well as a range of activation temperatures. The incorporation of GRHs into mortar exhibits a generally enhanced reinforcing effect compared to graphene nanoplatelets (GNPs) and multi-walled carbon nanotubes (MWNTs) because of its high specific surface area. SEM/TEM image analyses confirm that GRH has a corrugated graphene structure and clean edges at the atomic scale. GRH showed extremely high BET surface area (2274 m2/g) compared to those of multi-walled carbon nanotubes and GNPs (50–200 m2/g).