Effect of a Pre-dispersed GO:PCE Suspension on Compressive Strength and Density of Cement Paste

Abstract

This study examines whether a fixed preparation route using a pre-dispersed graphene oxide (GO) and polycarboxylate ether (PCE) suspension (GO:PCE suspension) produces a dosage-dependent compressive-strength response in cement pastes prepared with CEM I 42.5 N-SR0 and CEM II/B-LL 42.5 N, and whether apparent bulk density helps explain the resulting strength ranking. Graphene oxide (GO) was supplied as a 1 wt% aqueous dispersion (10 mg/mL) and combined with a polycarboxylate ether (PCE) at a fixed GO:PCE ratio of 1:5 by dry GO mass. After probe sonication, the prepared GO:PCE suspension was diluted with the mixing water to prepare pastes containing 0, 0.01, 0.03, and 0.05% GO by mass of cement. Compressive strength was measured at 7 and 28 days, and apparent bulk density was determined at 28 days. Both binders showed a non-linear response, with the 0.03% GO mixture giving the highest 28-day compressive strength, corresponding to increases of 23% for CEM I and 19% for CEM II/B-LL relative to the corresponding controls. Increasing the GO dosage to 0.05% did not provide a proportional additional benefit. Apparent bulk density showed only partial correspondence with strength, indicating that density alone could not explain the observed strength ranking.