Macro Performances and Microstructures of Graphene Oxide-Modified Cement Mortar Under Steam Curing Conditions

This study investigates the effects of incorporating polycarboxylate superplasticizer (PCE) and graphene oxide (GO) into cement mortar. The mechanical properties and durability of PCE-GO-modified cement mortar were compared under standard curing conditions and steam curing conditions. The results indicate that the optimal performance was achieved with a GO content of 0.04 wt% in a dosage of 0 to 0.06 wt%. Comparing the mortar’s performance under standard and steam curing conditions after 28 days revealed that the mechanical properties of the specimens cured under steam conditions were significantly lower than those cured under standard conditions. However, when 0.12 wt% PCE and 0.04 wt% GO were added, the filler effect of GO led to a 31.8% increase in flexural strength and a 28.4% increase in compressive strength for the specimens cured under steam conditions on the 28th day, effectively compensating for the strength loss caused by steam curing. The chloride ion penetration test and sulfate erosion test confirmed the optimal performance of the cement mortar specimens at 0.04 wt% GO, with corrosion resistance coefficients for flexural and compressive strength increasing by 68% and 70%, respectively, after 90 days of steam curing. Furthermore, SEM observations were conducted on the cement mortar specimens, revealing that GO not only fills the internal voids of the matrix but also organizes the hydration products of cement, resulting in a more compact matrix structure. This study enables PCE-GO-modified cement mortar to meet the requirements of early strength development without compromising the later-stage performance of the cement mortar due to steam curing-induced damage.