Effect of graphene oxide dispersion on hydration and carbonation performance of low-clinker cement

Artikel i vetenskaplig tidskrift, 2026

This study demonstrates how polycarboxylate ether-based superplasticizers (PCE) enable graphene oxide (GO) to improve the early hydration and mechanical performance of a low-clinker ternary cement, while also revealing an unexpected trade-off in carbonation behaviour. The ternary system consisted of ordinary Portland cement, slag, and limestone powder. The dispersion state of GO was evaluated through visual observation, ultraviolet-visible spectroscopy (UV-Vis) and dynamic light scattering (DLS), which confirmed that a PCE/GO mass ratio of 10 provided optimal stabilization. Isothermal calorimetry showed that 0.2 wt% GO accelerated hydration most effectively, while mortar testing demonstrated that 0.1 wt% GO increased 1-day compressive strength by 26 %. In-situ X-ray diffraction (XRD) further verified the promotion of early hydration phases. Under accelerated carbonation, however, 0.1 wt% GO increased the initial carbonation rate by 83.7 % without a corresponding increase in the total carbon dioxide (CO2) uptake, as determined by thermogravimetric analysis (TGA). This paradox suggests that GO may act as a nucleation agent for rapid surface precipitation of calcium carbonate (CaCO3), producing a dense outer layer that restricts further CO2 ingress. The finding that GO accelerates carbonation kinetics without enhancing total sequestration challenges prevailing assumptions in the literature and provides new guidance for the design of sustainable, nano-engineered, low-clinker binders, requiring a careful balance between early-age performance and long-term durability.