Antifoaming effect of graphene oxide nanosheets in polymer-modified cement composites for enhanced microstructure and mechanical performance

Polymer modified cement (PMC) composites attract attention due to their outstanding durability. However, reduced compressive strength caused by the air-entrainment restricts their application. Herein, a novel approach derived from 2D graphene oxide (GO) nanosheets to mitigate air-entrainment and enhance the mechanical performance of PMC is presented. The GO nanosheets tailor the polymer interaction with the cement matrix and act as an antifoaming agent in the GO-polymer modified composite (GOPMC). Microscopy and dispersion results demonstrated that GO nanosheets transform agglomerated polymer particles into a well-dispersed assembly and prevent their air-entraining effect. Chemical structure alteration of the air-entrained polymer by GO and promoted hydration was observed. Accordingly, the developed GOPMC without any conventional defoamer exhibited a 60.1% lower pore volume and improved 28-day tensile and compressive strengths by 59% and 33%, respectively, compared with PMC. The unveiled defoaming effect of the GO nanosheets introduces a new mechanism to fabricate hybrid cement composites.