Microstructural and polymer film interaction mechanisms: Insights of GO-reinforced polymer-modified cement composites

The effects of graphene oxide (GO) on cement hydration phases and polymer film formation in GO-reinforced polymer-modified cement (GOPMC) composites were investigated by analysing interactions of film chemical structure and cement hydration kinetics towards enhanced engineering performance. Chemical characterisation by FTIR and XRD analyses revealed that alterations of the cement matrix's chemical structure, such as slow Ethylene vinyl acetate (EVA) hydrolysis, increased calcium-silicate-hydrate (C–S–H) and portlandite Ca(OH)2, were more pronounced in GOPMC composites, indicating direct and robust involvement of GO during early-age hydration kinetics. Isothermal calorimetry displayed an increased heat flow of ∼7.2 % for GOPMC compared with the reference PMC composite. Notably, air voids of GOPMC composite revealed polymer film sheets intermingled with cement hydration products to promote elastic interconnections and microstructural uniformity. Accordingly, the GOPMC composite displayed ∼16 % higher tensile strength at 28 days versus the PMC composite, primarily attributable to GO nucleation, due to its seeding effect on cement hydration kinetics thereby inducing marginally slower EVA hydrolysis, increased C–S–H nucleation sites, and smaller-sized CH crystals while mechanically reinforcing polymer films. More significantly, GO reinforced the microstructure of the GOPMC composites with no apparent chemical interference of crucial film-forming properties. This research provides a fundamental understanding of this novel material's characteristic properties and framework of engineering performance optimization for future infrastructure applications.