Performance enhancement and environmental impact of graphene oxide-fly ash hybrid on cemented waste rock backfill

By enhancing performance and conserving resources, green materials promote the sustainability of construction projects. Controlling the cement usage of cemented waste rock backfill (CWRB) plays a central role in reinforcing effects, costs and environmental benefits for green mining construction, urgently needing new integrated strategies. This study discussed a green approach by replacing partial cement with only 0.0078 % industrial graphene oxide (GO) and 3.25 % fly ash (FA) to bond 74 % waste rock, and evaluated the performance enhancement and environmental impact. Microscopic quantitative porosity characterization revealed the hydration process adjustment. GO reduced the porosity of cement matrix by 24.4 % and refined pores by 26.7 %, with narrower pores and more sufficient surrounding cement hydration. Attributing to this mechanism, macroscopic performance demonstrates improvements across various aspects, with impermeability properties exhibiting the strongest correlation. Higher mechanical properties (maximum 25.7 % and 53.6 % in tensile and compression strength) accompany with transformation of failure mode, including complex strain field (maximum 19.6 % in fractal dimension) and mitigatory stress concentration. Furthermore, the cradle-to-gate assessment reveals that GO-FA maximumly reduces 24.3 % total price, 48 % CO₂ emissions and 47 % energy consumption per unit strength. This study promotes the understanding of GO enhancement mechanism and points out its great enhancement potential in sustainable pathways.