Dry Blending of Pristine Graphene Nanoplatelets (P-GNP) in Cement: A Proof-of-Concept Towards Sustainable Incorporation

The hydrophobic nature of pristine graphene (PG) limits its stability in aqueous media, creating challenges for the scalable implementation of conventional wet dispersion approaches in cementitious materials. This proof-of-concept study investigated dry dispersion of pristine graphene nanoplatelets (P-GNP) as an alternative route for incorporating PG into cement, with the potential to simplify processing and contribute towards more sustainable incorporation. Two PG products with different average lateral platelet sizes, PureGRAPH® 50 (PG50) and PureGRAPH® 5 (PG5), were milled with CEM II 52.5 N A-L cement under a fixed 1000-rotation condition. Three mortar mixes were prepared at a constant water-to-cement ratio of 0.50: a control (PG0), PG50_280 (280 g/m3) and PG5_28 (28 g/m3). Compressive strength, indirect tensile splitting strength, oxygen permeability index (OPI) and water absorption were evaluated. Particle-size distribution analysis showed that the milling procedure functioned primarily as a low-impact blending process without appreciably reducing cement particle size. SEM–EDS provided morphological evidence of P-GNP dispersion and changes in platelet profile following dry blending. PG5_28 exhibited the best overall performance, increasing 28-day compressive strength by 10.1% and 28-day ITS strength by 11.5%, both statistically significant, while numerical improvements were observed in selected durability parameters. These findings demonstrate the feasibility of low-impact dry blending for incorporating PG into cement while avoiding the suspension-stability requirements associated with wet dispersion. However, the individual effects of P-GNP dosage and lateral platelet size, together with the extent of platelet exfoliation during dry blending, require further investigation. This approach provides a potential pathway for PG-modified cement production, although industrial scalability and its environmental and energy implications require quantitative evaluation.