Influence of industrial graphene oxide on tensile behavior of cemented waste rock backfill

Abstract

Cemented waste rock backfill (CWRB) is an important supporting technology for underground engineering safety and waste recycling. However, the brittle nature of cementitious materials, particularly weak tensile behavior, always compromises the performance of the CWRB. In this study, the industrial graphene oxide (IGO) was adopted to reinforce the tensile behavior of the CWRB specimens and be mixed with fly ash to fabricate environmentally friendly, cost-effective, high-performance backfilling materials. The results showed that the tensile strength of the CWRB specimens was significantly improved up to approximately 230%, by only mixing 0.007 wt% IGO. The low water-to-cement (W/C) ratio benefited from the enhancing effects of the IGO on CWRB’s tensile performance. Molecular dynamics simulations further revealed the underlying nanoscale reinforcing mechanisms of IGO, indicating that the tensile strength enhancement is mainly due to GO nanosheets effectively improving the ductility of the nanocomposites and delaying the failure of cementitious materials. The microstructure characterization proved that IGO could generate nucleation effects and pore infilling effects to optimize the microstructure in the interfacial transition zone (ITZ) of CWRB. Acoustic emission monitoring and digital photography characterization technologies implied that incorporating IGO could effectively reduce the micro-damage degree of the CWRB specimens during the failure process. This phenomenon ensures the integrity of the specimen during the destabilization failure process and reinforces resistance to the compressive load. This research not only broadens our understanding of GO in enhancing cementitious composites but also inspires the potential application of the IGO for strengthening the performance of cemented rockfill and the sustainability of waste rock recycling.