Reducing carbon emissions by strengthening blended cement’s functional properties with graphene oxide as a reinforcing filler

Abstract

Cement production accounts for approximately 8% of global CO2 emissions. Cement is made from crushed limestone and aluminosilicate clay and roasted in kilns to produce calcium oxide, the desired product, and CO2.  CO2 accounts for 600 grams of the byproduct per kilogram of cement produced. To some extent, the high CO2 emissions have been addressed in the past by using supplementary cementitious materials (SCMs) to replace the clinker. These are industrial (like fly ash) and agricultural wastes (like rice husk) that have already been processed and do not further release any CO2. However, such substitutions often result in a loss of strength. This can be addressed by incorporating nanoparticles to modify or re-engineer the concrete mix. One such nanomaterial is graphene oxide (GO), which is expected to reduce CO2 emissions because the same structural task can be achieved with a lesser amount of cement, since graphene oxide enhances the strength of the concrete mix. This research uses research-grade graphene oxide (instead of pristine graphene due to dispersibility issues) in small percentages (0.01% to 0.05% by weight of cement) to observe the enhancement in mechanical strength and workability of the concrete mix. While the mechanical strength increased significantly, the workability of samples infused with graphene oxide poses a problem because as we add more GO to our cement mix, the higher the slump value of the mix becomes.