Long-term performance and protective mechanism of graphene oxide-geopolymer anticorrosive coatings: Molecular dynamics simulation and exposure experiment

This research is investigated on long-term performance evolutionary laws and protection mechanisms of graphene oxide-geopolymer anticorrosive coatings. Although previous studies have demonstrated the short-term corrosion resistance of graphene oxide–modified geopolymer systems, systematic understanding of their long-term corrosion resistance and degradation mechanisms under complex service environments remains limited. Regulatory effects of water-to-binder ratio and graphene oxide dosage on macroscale anticorrosive performance, mechanical stability and microstructural evolution of coatings are systematically investigated based on multi-scale research methods. Results demonstrate that when w/b is 0.47 and graphene oxide dosage is 0.03%, the coating exhibits optimal comprehensive performance. Chloride ion diffusion coefficient is reduced by 60.8% and corrosion rate is only 23% compared with reference group, and the attenuation amplitude of mechanical indicators is significantly reduced. Graphene oxide synergistically enhances physical barrier and chemical immobilization capacities of coating against chloride ions by inducing densification of C-(A)-S-H, constructing stable hydrogen bond network, optimizing pore structure and hydrophobicity. Finally, based on multi-source experimental data and meteorological parameter, service life prediction model is established and the calculation results indicate that long-term service reliability of graphene oxide-geopolymer coatings remains above 90%.