Uniform dispersion of graphene in asphalt emulsion using an aerosol- based approach: An experimental-simulation study

WL Zhu and AH Zhang, CONSTRUCTION AND BUILDING MATERIALS, 489, 142170 (2025).

DOI: 10.1016/j.conbuildmat.2025.142170

A key challenge in developing high-performance, graphene-modified asphalt binders is preventing premature agglomeration of graphene flakes during the mixing process. In this study, we propose an aerosol-based method for producing graphene-modified asphalt emulsion (GMAE), wherein graphite is electrically exploded to generate few-layer graphene aerosols that are directly introduced into a cationic asphalt emulsion under ambient conditions. Fluorescence microscopy and X-ray diffraction confirm that graphene is uniformly dispersed, with no large black inclusions observed, and a characteristic (002) peak verifying stable embedding of few-layer graphene. To clarify the mechanism underlying this uniform dispersion, molecular dynamics (MD) simulations were performed to examine re-agglomeration tendencies under varying conditions. The results reveal that, in a cationic asphalt emulsion, positively charged surfactant head groups anchor in the aqueous phase while their hydrophobic tails interlock with asphalt molecules, creating a cohesive interfacial network that physically and electrostatically inhibits graphene flakes from coalescing. Conversely, using an anionic surfactant or removing water leads to patchier coverage or asphalt coalescence near the graphene substrate, respectively, which can promote partial clustering. These findings demonstrate that uniform graphene dispersion in asphalt emulsions arises from the synergy between (i) the aerosol-based preparation that prevents early flake aggregation, and (ii) the robust surfactant-water interfacial layer that continues to impede flake-flake contact during mixing. Overall, these experimental and computational insights provide a viable route for producing GMAE with enhanced durability, improved microstructural uniformity, and minimized agglomeration, paving the way for nextgeneration pavement materials.

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