Study on strength, toughness, and energy dissipation capability of coal gangue grouting materials optimized with graphene oxide-nanosilica

The “grouting for coalburst prevention” technology in roadways imposes new “high toughness” requirements for grouting materials. To overcome the poor toughness of existing grouting materials while reducing coal gangue solid waste emissions, this study established performance optimization targets for impact-resistant grouting materials through theoretical analysis. By modifying coal gangue powder–cement with graphene oxide and nanosilica (PCGN), a novel eco-friendly grouting material featuring “high strength and high toughness” was developed. Uniaxial compression, tensile, and shear strength tests combined with SEM and XRD were used to analyze the mechanical property variation patterns of the PCGN, along with the effects of modification mechanisms of graphene oxide and nanosilica on the composite cementitious materials. By integrating uniaxial stress‒strain curves, digital image correlation, and acoustic emission techniques, we quantitatively analyzed the postpeak dissipation energy, bursting energy index, static toughness, and strain field evolution patterns of the PCGN. Research findings indicate: Graphene oxide significantly enhanced the mechanical properties of PCGN. At an optimal mass fraction of 0.06%, the compressive strength and tensile strength of the PCGN increased by 24.8% and 17.81%, respectively. The mechanism involves the binding of surface functional groups of graphene oxide with Ca 2+ ions to promote calcium silicate hydrate gel nucleation, while its network skeleton structure strengthens the bonding between hydration products. Nanosilica and coal gangue significantly enhanced the postpeak energy dissipation capacity and toughness of the PCGN. This study provides an environmentally friendly and high-performance new material for grouting to prevent coalburst in mine roadways.